
Jeff's birthday is one week away, and we're all pretty excited about it.

Well, at least I am. And I felt like making the ultimate birthday cake. I've also been wanting to try out Christina Tosi's homemade Funfetti cake for about nine months. The concept behind it--let's spend hours baking something that normally takes about five minutes to throw together--is, if you think about it, so me. I'm the kind of person who will spend a month painting a watercolor while my contemporaries blithely turn out splashy creations at the rate of one per day. What is my problem?
That's a question for another time. But this recipe results in something that accurately duplicates yet is better than your standard Funfetti-with-canned-frosting cake because it has the secret ingredients of love and toil and dude I spent my entire Friday afternoon making this for you. It also has some crunchy things happening that you won't get anywhere else. Christina Tosi is a wonderful maniac for putting this recipe together. Her Momofuku Milk Bar cookbook is by far my favorite cookbook this year and is definitely in my all-time top five. Look: it contains a recipe for something called "liquid cheesecake" and it's everything you imagine it to be. Buy this book. Learn from it. Worship it.
Here's the giant recipe. My notes are in italics, and I apologize for the wonky format. It's a Typepad problem.

Birthday Cake
makes 1 quarter sheet pan
- 4 tablespoons (½ stick, 55g) butter, at room temperatue
- ⅓ cup (60g) vegetable shortening
- 1¼ cups (250g) granulated sugar
- 3 tablespoons (50g) light brown sugar, tightly packed
- 3 eggs
- ½ cup (110g) buttermilk
- ⅓ cup (65g) grapeseed oil <-- vegetable oil also works
- 2 teaspoons (8g) clear vanilla extract <-- regular vanilla also works
- 2 cups (245g) cake flour
- 1½ teaspoons (6g) baking powder
- ¾ teaspoon (3g) kosher salt
- ¼ cup (50g) rainbow sprinkles
- Pam or other nonstick cooking spray (optional)
- 2 tablespoons (25g) rainbow sprinkles
Preheat the oven to 350.
Combine the butter, shortening, and
sugars in the bowl of a stand mixer fitted with the paddle attachment
and cream together on medium-high for 2 to 3 minutes. Scrape down the
sides of the bowl, add the eggs, and mix on medium-high for 2 to 3
minutes. Scrape down the sides of the bowl once more.
On low speed, stream in the
buttermilk, oil, and vanilla. Increase the mixer speed to medium-high
and paddle for 4 to 6 minutes, until the mixture is practically white,
twice the size of your original fluffy butter-and-sugar mixture, and
completely homogenous. Don’t rush the process. You’re basically forcing
too much liquid into an already fatty mixture that doesn’t want to make
room for the liquid. There should be no streaks of fat of liquid. Stop
the mixer and scrape down the sides of the bowl.
On very low speed, add the cake flour,
baking powder, salt, and the 50g (¼ cup) rainbow sprinkles. Mix for 45
to 60 seconds, just until your batter comes together. Scrape down the
sides of the bowl. Please note: the batter is delicious. Jeff popped into the kitchen and ate, I don't know, two tablespoons of it.
Pam-spray a quarter sheet pan and line
it with parchment, or just line the pan with a Silpat. Using a spatula,
spread the cake batter in an even layer in the pan. Sprinkle the
remaining 25g (2 tablespoons) rainbow sprinkles evenly on top of the
batter.
Bake the cake for 30 to 35 minutes.
The cake will rise and puff, doubling in size, but will remain slightly
buttery and dense. At 30 minutes, gently poke the edge of the cake with
your finger: the cake should bounce back slightly and the center should
no longer be jiggly. Leave the cake in the oven for an extra 3 to 5
minutes if it doesn’t pass these tests. My cake took 30 minutes to bake completely.
Take the cake out of the oven and cool
on a wire rack or, in a pinch, in the fridge or freezer (don’t worry,
it’s not cheating). The cooled cake can be stored in the fridge, wrapped
in plastic wrap, for up to 5 days.

Birthday Cake Soak
makes about 60g (¼ cup)
- ¼ cup (55g) milk
- 1 teaspoon (4g) clear vanilla extract
Whisk together the milk and vanilla in a small bowl.

Birthday Cake Frosting
makes about 430g (2 cups)
- 8 tablespoons (1 stick, 115g) butter, at room temperature
- ¼ cup (50g) vegetable shortening
- 2 ounces (55g) cream cheese
- 1 tablespoon (25g) glucose <-- I got mine on Amazon
- 1 tablespoon (18g) corn syrup
- 1 tablespoon (12g) clear vanilla extract <-- regular vanilla works too
- 1¼ cups (200g) confectioners’ sugar
- ½ teaspoon (2g) kosher salt
- pinch (0.25g) baking powder <-- what an idea!
- pinch (0.25g) citric acid <-- I got mine on Amazon
Combine the butter, shortening, and
cream cheese in the bowl of a stand mixer fitted with the paddle
attachment and cream together on medium-high for 2 to 3 minutes, until
the mixture is smooth and fluffy. Scrape down the sides of the bowl.
With the mixer on its lowest speed,
stream in the glucose, corn syrup, and vanilla. Crank the mixer up to
medium-high and beat for 2 to 3 minutes, until the mixture is silky
smooth and a glossy white. Scrape down the sides of the bowl.
Add the confectioners’ sugar, salt,
baking powder, and citric acid and mix on low speed just to incorporate
them into the batter. Crank the speed back up to medium-high and beat
for 2 to 3 minutes, until you have a brilliant stark white, beautifully
smooth frosting. It should look just like it came out of a plastic tub
at the grocery store! Use the frosting immediately, or store it in an
airtight container in the fridge for up to 1 week.

Birthday Cake Crumb
makes for 275g (2¼ cups)
- ½ cup (100g) granulated sugar
- 1½ tablespoons (25g) light brown sugar, tightly packed
- ¾ cup (90g) cake flour
- ½ teaspoon (2g) baking powder
- ½ teaspoon (2g) kosher salt
- 2 tablespoons (20g) rainbow sprinkles
- ¼ cup (40g) grapeseed oil <-- vegetable oil also works
- 1 tablespoon (12g) clear vanilla extract <-- again, regular works
Heat the oven to 300°F.
Combine the sugars, flour, baking
powder, salt, and sprinkles in the bowl of a stand mixer fitted with the
paddle attachment and mix on low speed until well combined.
Add the oil and vanilla and paddle
again to distribute. The wet ingredients will act as glue to help the
dry ingredients form small clusters; continue paddling until that
happens.
Spread the cluster on a parchment- or
Silpat-lined sheet pan. Bake for 20 minutes, breaking them up
occasionally. The crumbs should still be slightly moist to the touch;
they will dry and harden as they cool.
Let the crumbs cool completely before
using in a recipe or scarfing by the handful. Oh you will want to do that. You can get away with eating maybe 1/4 cup of them. This recipe makes a lot. Stored in an airtight
container, the crumbs will keep fresh for 1 week at room temperature or 1
month in the fridge or freezer.

Assembly
You will need a 6" cake ring and two 20"x3" pieces of acetate. Come on. I know you don't have them. Add them to your Amazon wish list along with the glucose and the citric acid, hopefully get them for Christmas or your birthday, and wait for an excuse to use them.
Put a piece of parchment or a Silpat
on the counter. Invert the cake onto it and peel off the parchment or
Silpat from the bottom of the cake. Use a 6" cake ring to stamp out 2
circles from the cake. These are your top 2 cake layers. The remaining
cake “scrap” will come together to make the bottom layer of the cake.

- layer 1, the bottom -
Clean the cake ring and place it in
the center of a sheet pan lined with clean parchment or a Silpat. Use 1
strip of acetate to line the inside of the cake ring.
Put the cake scraps in the ring and use the back of your hand to tamp the scraps together into a flat even layer.
Dunk a pastry brush in the birthday cake soak and give the layer of cake a good, healthy bath of half of the soak.
Use the back of a spoon to spread one-fifth of the frosting in an even layer over the cake.
Sprinkle one-third of the birthday
crumbs evenly over the top of the frosting. Use the back of your hand to
anchor them in place.
Use the back of a spoon to spread a second fifth of the frosting as evenly as possible over the crumbs. This is quite impossible. Give it your best shot and try not to get too uptight about it. Neatness doesn't really matter.
- layer 2, the middle -
With your index finger, gently tuck
the second strip of acetate between the cake ring and the top ¼ inch of
the first strip of acetate, so that you have a clear ring of acetate 5
to 6 inches tall—high enough to support the height of the finished cake.
Set a cake round on top of the frosting, and repeat the process for
layer 1 (if 1 of your 2 cake rounds is jankier than the other, use it
here in the middle and save the prettier one for the top). This acetate stuff is truly a pain in the ass, but it's worth the hassle, I tell you, if only for the satisfaction you will feel when you peel it off later.
- layer 3, the top -
Nestle the remaining cake round into
the frosting. Cover the top of the cake with the last fifth of the
frosting. Give it volume and swirls, or do as we do and opt for a
perfectly flat top. Garnish the frosting with the remaining birthday
crumbs.
Transfer the sheet pan to the freezer
and freeze for a minimum of 12 hours to set the cake and filling. The
cake will keep in the freezer for up to 2 weeks.
At least 3 hours before you are ready
to serve the cake, pull the sheet pan out of the freezer and, using
your fingers and thumbs, pop the cake out of the cake ring. I've also set the cake on top of smaller, upside-down bowl and pushed down on the ring. It's easier than using your hands. Gently peel
off the acetate and transfer the cake to a platter or cake stand. Let it
defrost in the fridge for a minimum of 3 hours (wrapped well in
plastic, it can be refrigerated for up to 5 days).
Slice the cake into wedges and serve.

Jeff's comment:
"[This]
was glorious food and even made the cream soda that washed it down
taste better. I described it as the Platonic ideal of a Funfetti cake."