Birthday Cake Petit Fours

1. Make the Cake: Preheat the oven to 350°F. Grease and flour a 9-inch square baking pan.

2. In the bowl of an electric mixer fitted with the paddle attachment, cream the butter and sugar until light and fluffy, about 4 minutes.

3. Add the eggs one at a time, mixing on medium speed until each is fully incorporated. Scrape the bowl well, then add the vanilla and mix to combine.

4. In a medium bowl, whisk together the flour, baking powder and salt. In a liquid measuring cup, combine the milk with ¼ cup warm water. Add the flour mixture to the mixer and mix on low speed to combine, about 2 minutes. Pour in the milk mixture in a slow, steady stream and mix to combine, about 1 minute.

5. Pour the batter into the prepared pan. Bake the cake until a toothpick inserted into the center comes out clean, 30 to 35 minutes (the cake will not spring back when you touch it in the middle). Cool in the pan for 15 minutes, then turn out onto a wire rack to cool completely.

6. Make the Filling: In the bowl of an electric mixer fitted with the paddle attachment, cream the butter and confectioners’ sugar until light and fluffy, about 2 minutes. Add the vanilla and cream, and mix to combine.

7. Use a long serrated knife to cut the cake horizontally in half to create two even layers. Place the bottom layer on a baking sheet, then scoop about two-thirds of the frosting on top and spread into an even layer. Place the second layer on top and use the remaining frosting to evenly and smoothly frost the surface of the cake. Chill for 30 minutes.

8. Make the Icing: In a medium-size heat-proof bowl, whisk together the confectioners’ sugar, corn syrup, vanilla extract ⅔ cup water. Set the bowl over a medium pot of simmering water and heat, stirring occasionally, until the mixture is smooth and homogenous. Let cool. (The icing will thicken as it cools.)

9. Use a sharp knife to cut about ¼ inch off each side of the chilled cake to create flat edges. Cut the cake vertically into six even strips, then horizontally into six even strips, making 36 squares.

10. Place a wire rack over a baking sheet and arrange the petit fours on it. Use a ladle to pour the icing over each cake. It should easily run down the sides and fully coat the cakes. If it gets too thick, warmit up slightly by placing it back on the pot of simmering water and stirring occasionally. You may need to lift the rack off the baking sheet and pour the excess icing back into the bowl to reuse.

11. Once the cakes are glazed, garnish each with a few sprinkles. Leave the cakes to set for 15 minutes; the icing will set up firm.