Marbled lemon blueberry butter cake recipe

Ingredients

• 2 sticks (8 ounces) unsalted butter, at room temperature
• 2 cups sugar
• 2 tsp grated lemon zest
• 1½ tsp lemon extract
• 7 egg whites
• 3 cups cake flour
• 4 tsp baking powder
• ½ tsp salt
• 1¼ cups milk
• Fresh blueberries, for decoration
• 1 cup sugar
• ¼ cup water
• 2 eggs
• 3 sticks (12 ounces) unsalted butter, at room temperature
• 2 tbsp freshly squeezed lemon juice suggest adding some zest as well for added flavour)