Mascarpone cream cake with boozy berries - chinese grandma

Ingredients

• 2 cups cake flour or 1 3/4 cups all purpose flour plus 1/4 cup cornstarch
• 1 teaspoon baking powder
• 1 teaspoon baking soda
• 1/2 teaspoon salt (1/4 teaspoon if using salted butter)
• 1/2 cup (1 stick) butter, softened
• 1 cup sugar
• 1 teaspoon vanilla extract
• 2 large eggs
• 1 cup well-shaken buttermilk
• 1/2 cup Fino (dry) sherry
• 1/2 cup sugar
• 4 cups mixed berries, cut if large
• 8 ounces (1 cup) mascarpone
• 1 cup chilled heavy cream
• 1/4 cup sugar