Prep the base — Preheat your oven to 350°F and grease your pans thoroughly. Cream the softened butter and granulated sugar together until the mixture looks pale, fluffy, and significantly increased in volume.
Incorporate the eggs — Add the eggs one at a time, beating well after each addition. This builds a strong emulsion that prevents the batter from curdling when you add the liquid soda later.
Mix dry ingredients — Whisk the flour, baking powder, and salt in a separate bowl. Sifting these together ensures there are no leavening clumps, which could cause uneven holes in your cake.
Alternate liquids — Begin adding the flour mixture and the lemon-lime soda to the butter mixture, starting and ending with the flour. Mix on low speed just until the white streaks disappear to avoid overworking the gluten.
Fold in the fruit — Gently fold in the chopped maraschino cherries and the vanilla and almond extracts using a spatula. You want to see red flecks throughout the pale batter without turning the whole bowl pink.
Bake to golden — Pour into the prepared pans and bake until a tester comes out clean and the edges pull slightly away from the sides. The aroma of toasted sugar and cherries should fill the kitchen.
Whip the frosting — Beat the softened butter with powdered sugar, adding the maraschino cherry juice and almond extract gradually. Watch for a glossy, pale pink consistency that holds a stiff peak.
Decorate and set — Once the cake is completely cool, spread the frosting generously. Garnish with whole cherries immediately so they stick to the fresh frosting before it develops a slight crust.