Berry Swirl Bundt Cake

Name: Berry Swirl Bundt Cake
Ingredients: 6 egg whites; 1 3/4 cups (14 oz./435 g) granulated sugar; 3 1/2 cups (14 oz./440 g) cake flour; 4 tsp. baking powder; 2 tsp. kosher salt; 1/2 tsp. baking soda; 24 Tbs. (3 sticks) (12 oz./375 g) unsalted butter, at room temperature; 3 tsp. vanilla extract; 1 cup (8 fl. oz./250 ml) buttermilk; 1/2 oz. (15 g) freeze-dried strawberries or raspberries, ground into a fine powder; 1 or 2 drops pink food coloring (optional); Confectioners’ sugar for dusting; Lightly sweetened whipped cream for serving; Fresh berries for serving