01 -
Preheat oven to 350°F (176°C). Prepare three 8-inch cake pans with non-stick spray and parchment paper on the bottom. Combine flour, sugar, baking powder, and salt in a large mixing bowl. In another bowl, mix milk, vegetable oil, vanilla extract, and eggs. Slowly incorporate wet ingredients into the dry mixture. Gradually add water to the batter while mixing on low speed. Divide batter evenly into the pans and bake for 24-28 minutes. Let cool for 2-3 minutes, then transfer to a cooling rack.
02 -
Puree berries and water in a food processor until smooth. Combine sugar and cornstarch in a saucepan, then stir in puree. Cook on medium heat, continuously stirring until the mixture thickens and boils, about 8-10 minutes. Let boil for 1 minute, then remove from heat. Cool completely in the refrigerator.
03 -
Whip heavy cream, powdered sugar, and vanilla extract until soft peaks form. Add mascarpone cheese and whip until stiff peaks form. Trim domes off cake layers using a serrated knife. Place one cake layer on a serving plate, piping a frosting dam around the edge with a piping tip. Add half the berry filling inside the dam, followed by additional frosting to fill the gap. Repeat with the second layer. Add the final cake layer and frost the exterior. Decorate with frosting swirls and fresh berries. Refrigerate until serving.