All of these birthdays just give my obsession some legitimacy.  The cake is from Amy Sedaris. and the frosting is from Emma Laperruque and Food52.

INGREDIENTS

Cake

1 1/2 sticks unsalted butter
1 1/2 cups sugar
2 eggs
2 teaspoons pure vanilla extract
2 1/2 teaspoons baking powder
1/4 teaspoon salt
2 1/2 cups flour
1 1/4 cups milk

Chocolate Frosting

³/₄ cup (170 grams) unsalted butter, melted and cooled slightly
1 cup (85 grams) natural cocoa powder
1 ¹/₂ teaspoons vanilla extract
³/₄ teaspoon kosher salt
4 ¹/₂ cups (513 grams) powdered sugar
¹/₂ cup strong, cold coffee, plus more as needed

DIRECTIONS

Cake

Put butter in mixer and beat at medium speed until somewhat smooth. Pour in sugar and beat well. Add 2 eggs. Mix well. Add: vanilla, baking powder, salt, flour, and milk. Beat until it looks like it is supposed to and pour into two 7″ cake pans. Bake for 25 minutes or until golden brown.

Frosting

Make the chocolate frosting. Combine the butter and cocoa in the bowl of a standing mixer fitted with the whisk attachment. Mix until smooth, scraping down as needed. Add the vanilla and salt. Mix again. Alternately add the powdered sugar and coffee, beating until light and fluffy. (If it doesn’t start to fluff up, it may be too warm. Chill for a little while until thicker, then beat again.) 

Set the first layer on your serving platter or a rotating turntable if you have one. Add about 1 cup frosting on top and spread evenly (I like an offset spatula best here). Top with the second cake layer. Add another 1 1/2 cups frosting to the top and spread evenly over the top, then the sides. Add more frosting as needed. Use the offset spatula or a spoon to create swooshes. Slice and eat or refrigerate until you’re ready to eat.