Preheat oven to 350°. Line a 171⁄4x 111⁄2 -inch rimmed baking sheet with parchment paper and spray with cooking spray.
In a large bowl, beat together butter and sugar with a mixer at high speed until light and fluffy, approximately 3 minutes. Add eggs, one at a time, beating well after each addition. Add almond extract, beating until incorporated.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Add flour mixture to butter mixture, alternately with milk, beginning and ending with flour mixture, beating well after each addition. Pour batter into prepared pan. Using an offset spatula, spread batter evenly. Tap pan several times on countertop to reduce air bubbles in batter.
Bake until a wooden pick inserted near center comes out clean, 13 to 15 minutes. Let cake cool completely in pan. Freeze for 1 hour.
Using a 2-inch round cutter, cut 24 circles from frozen cake, discarding scraps. Let cake rounds thaw completely.
Place Almond Buttercream in a piping bag fitted with a large open-star tip*. Pipe a buttercream rosette onto 12 cake rounds. Top each with a plain cake round. Pipe a buttercream rosette onto the top. Garnish with sliced almonds, if desired.
*We used an Ateco #865 tip.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/almond-cakes/