Desserts for the Fourth of July: Ina Garten's Berry Cake, Strawberry Pretzel Salad, Chocolate-Covere

Ingredients

• 18 tablespoons (2 1/4 sticks) unsalted butter, at room temperature
• 3 cups sugar
• 6 extra-large eggs, at room temperature
• 1 cup sour cream, at room temperature
• 1 1/2 teaspoons pure vanilla extract
• 3 cups flour
• 1/3 cup cornstarch
• 1 teaspoon kosher salt
• 1 teaspoon baking soda