Blueberry Coffee Cake

Bahan-bahan (12 porsi)

• ½ cup butter (softened)
• 1 cup sugar
• 2 eggs
• 1 tablespoon lemon zest (or the zest of (1) large lemon)
• 2 tablespoons fresh lemon juice
• 2 teaspoons vanilla extract
• 1 cup all-purpose flour*
• ½ teaspoon baking powder
• ½ cup sour cream
• 1 cup fresh blueberries
• ⅔ cup brown rice flour
• ¼ cup tapioca starch
• ¼ cup potato starch
• ½ teaspoon xantham gum
• ⅔ cup all-purpose flour**
• ⅔ cup brown sugar
• ¼ cup butter (melted)
• ⅔ cup brown rice flour