Lemon Blueberry Cake

Ingredients

• ¾ cup sour cream
• 1 Tbsp baking powder
• 4 cups powdered sugar
• 2 cups sugar
• 12 oz. cream cheese
• 2 tsp vanilla extract
• 1 Tbsp vanilla extract
• 3 cups all-purpose flour
• 1 cup unsalted butter
• ¼ tsp salt
• optional} additional blueberries
• 6 large egg whites
• ¼ cup lemon juice
• 2 tsp lemon juice
• 1 Tbsp lemon zest
• 2½ cups fresh blueberries
• 1 cup milk