01 - Preheat the oven to 350°F. Grease and line three 8-inch round cake pans with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
03 - In a large bowl, beat butter and sugar together until light and fluffy, about 3-4 minutes.
04 - Add eggs one at a time, beating well after each addition. Mix in vanilla and almond extract.
05 - Gradually add the flour mixture in three parts, alternating with buttermilk, beginning and ending with the flour mixture.
06 - Add green food coloring and mix until the batter reaches your desired shade of green.
07 - Divide the batter evenly among the prepared pans and smooth the tops. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
08 - Allow cakes to cool in the pans for 10 minutes, then turn out onto wire racks to cool completely.
09 - Beat butter until creamy. Gradually add powdered sugar, mixing on low speed. Add milk, vanilla, and salt; beat on high until fluffy and smooth.
10 - Place one cake layer on a serving plate. Spread with frosting, then top with the next layer; repeat. Frost the top and sides of the cake.
11 - Decorate with green sprinkles or edible shamrocks.