Step 1

Set an oven rack in the middle position. Preheat the oven to 350 degrees F.

Step 2

Grease the bottom of an 8-by-12 inch metal baking pan and line the bottom with parchment. Then grease and flour the bottom and sides of the pan. Set aside.

Step 3

For the cake: sift together the flour and baking powder. Add the salt and stir to combine.

Step 4

In the bowl of a stand mixer fitted with the paddle attachment, add 1 cup of butter and sugar and beat on medium-high speed until light and fluffy, 2 to 3 minutes. Using a rubber spatula, scrape the bottom and sides of the bowl, as needed. Add the eggs, 1 at a time, beating on medium speed and scraping down the sides of the bowl between additions. Add the vanilla and almond extracts and beat to combine. On low speed, mix in half of the flour mixture, then mix in the milk. Mix in remaining flour mixture until just combined. Transfer the batter to the prepared pan and bake until a tester comes out clean, 18 to 20 minutes. Transfer to a rack to cool slightly, then unmold and cool completely.

Step 5

To make the cake filling, using a serrated knife, cut the cake into an 8x8-inch square. Set aside. Crumble the portion of the cake that was removed and reserve 2 1/2 cups. Add the remainder of the cake crumbs to a large mixing bowl along with the remaining 1/4 cup melted butter, jam and almonds. Mix well (your hands are the best tool here) to make a spreadable filling.

Step 6

To assemble the cake, use a serrated knife to split the cake crosswise into 2 halves. Arrange both halves so they’re facing cut-side up. Brush the cake with about 2/3 of the cooled almond syrup. With a small offset spatula, gently spread the jammy filling over the entire bottom half of the cake and top with the top half of the cake, cut side down. Press gently to adhere. Flip the cake so the flat bottom is now facing up, to create a flat top. Freeze the cake until firm, 1 hour.

Step 7

With a serrated knife, cut off the rough sides on the frozen cake and cut into 16 squares. Set the cake on a cooling rack over a parchment-lined baking sheet.

Step 8

Coat the cakes 1 at a time by pouring the icing around the edges and letting it drip down to coat the sides, then fill in the top. (Set the bowl over hot water and stir if it begins to thicken before you are done.) Top with sprinkles or non pareils before the icing begins to set.

Step 9

Combine the sugar and water in a small saucepan over low heat and cook to dissolve the sugar, 2 to 3 minutes. Remove from the heat. Add the almond extract and stir to combine. Cool completely.

Step 10

Melt the chocolate chips or candy melts in a double boiler and stir until smooth.

Step 11

In the bowl of a stand mixer fitted with the whisk attachment, add the confectioner’s sugar, corn syrup, hot water and vanilla. Mix on low speed until smooth. Add the melted chocolate and continue to mix to make a very smooth, pourable icing, about the consistency of molasses. Add food coloring as desired.