gluten free pancake recipe

1 cup gluten-free all-purpose flour blend - 1 tablespoon sugar - 1 teaspoon baking powder - 1/2 teaspoon baking soda - 1/4 teaspoon salt - 1 cup buttermilk (or dairy-free milk with 1 tablespoon lemon juice or vinegar) - 1 large egg - 2 tablespoons melted butter or coconut oil (plus more for cooking) - 1 teaspoon vanilla extract