Chantilly Cream Cake

Name: Chantilly Cream Cake
Ingredients: 3 cups (about 11 1/4 ounces) bleached cake flour (such as Swans Down), plus more for dusting cake pans; 1 tablespoon baking powder; 1 teaspoons kosher salt; 2 cups granulated sugar; 3/4 cup (6 ounces) unsalted butter , at room temperature, plus more for greasing cake pans; 1 tablespoon vanilla extract; 4 large eggs , at room temperature; 1 cup whole milk , at room temperature; 1/4 cup elderflower syrup (such as Belvoir Farm); 1 cup freeze-dried red berries (such as strawberries and raspberries) (about 1 ounce); 1/4 cup powdered sugar; 1 1/2 cups heavy whipping cream; 1 teaspoon vanilla extract; 8 ounces mascarpone cheese; 1 1/4 teaspoons vanilla extract; 1 1/4 teaspoons elderflower syrup (such as Belvoir Farm); 2 cups heavy whipping cream, divided; Fresh berries (such as strawberries, raspberries, blueberries, and blackberries)