01 - Preheat oven to 350°F. Grease and line three 8-inch round cake pans with parchment paper.
02 - Whisk together flour, baking powder, baking soda, and salt in a medium bowl. Set aside.
03 - Beat butter and sugar in a large bowl until light and fluffy, approximately 3-4 minutes.
04 - Add eggs one at a time, beating thoroughly after each addition. Blend in vanilla and almond extracts.
05 - Gradually add flour mixture in three portions, alternating with buttermilk. Begin and end with the dry ingredients, mixing until just combined.
06 - Incorporate green food coloring, mixing until the batter achieves the desired vibrant green shade.
07 - Divide batter evenly among prepared pans, smoothing tops. Bake for 25-30 minutes until a toothpick inserted into the center comes out clean.
08 - Let cakes cool in pans for 10 minutes, then transfer to wire racks to cool completely.
09 - Beat butter until creamy. Gradually incorporate powdered sugar on low speed. Add milk, vanilla, and salt. Whip on high speed until fluffy and smooth.
10 - Tint a portion of frosting with green food coloring if decorative contrast is desired.
11 - Place first cake layer on serving plate. Spread with frosting, add next layer, and repeat. Frost the entire exterior—top and sides—until smooth and evenly coated.
12 - Garnish with green sprinkles or edible shamrocks for festive presentation.