Zutaten:

• 1 cup blueberries
• 1 teaspoon lemon juice
• 1 tablespoon flour
• 1 cup flour
• 1 teaspoon baking powder
• ½ teaspoon salt
• ¼ teaspoon cinnamon
• ½ cup butter (at room temperature)
• ¾ cup sugar
• 2 large eggs
• 1 teaspoon vanilla
• 2 teaspoons lemon zest (optional)
• ¾ cup fresh or frozen (thawed) blueberries
• 1 cup butter (at room temperature)
• 3 cups powdered sugar
• 2 teaspoons vanilla extract
• ¼ teaspoon salt
• 2-3 tablespoons heavy cream (as needed)
• 1 teaspoon lemon zest (optional)