In a medium saucepan, combine 3 cups of pitted sweet cherries and purée until smooth. Simmer for about 15 minutes until thickened. Allow to cool completely.

In a large mixing bowl, whisk together 2.5 cups of cake flour, 1.5 cups of sugar, 1 tablespoon of baking powder, 0.5 teaspoon of baking soda, and 0.5 teaspoon of kosher salt.

Add in 0.75 cups of softened unsalted butter and mix until the mixture resembles coarse sand.

Whisk together the cooled cherry puree, 0.5 cups of buttermilk, 0.25 cups of vegetable oil, 4 large egg whites, 1 teaspoon of vanilla extract, and 0.25 teaspoon of almond extract if using. Pour into dry ingredients in two batches, mixing gently until just combined.

Preheat oven to 350°F (175°C) and grease two 8-inch round pans. Divide the batter evenly and smooth the tops. Bake for 30 to 35 minutes, or until a toothpick comes out clean. Cool in the pans for 10 minutes before transferring to a wire rack.

For frosting, beat together 0.5 cups of softened unsalted butter and 8 oz of softened cream cheese until creamy. Gradually add 4 cups of powdered sugar until blended, then mix in remaining cherry puree until thick and spreadable.

Place one cake layer on a serving plate, spread frosting, and add cherry jam if desired. Top with the second layer and frost the top and sides. Chill in the refrigerator for 30 minutes before serving.