1. Preheat the oven to 400 degrees F. Grease a 24-cup mini muffin pan. 2. In a large bowl, whisk together the flour, sugar, baking powder and salt. 3. In a separate large bowl, stir together the milk, lemon juice, 1/4 cup melted butter, egg, yogurt, vanilla and lemon zest. This mixture may look clumpy and/or curdled; that?s normal! 4. Add the wet ingredients to the dry ingredients, stirring just to combine. Spoon the batter into the prepared muffin tin. 5. Bake 12 to 14 minutes, or until a toothpick inserted in the center of a muffin comes out clean. 6. Cool the muffins in the pan on a wire rack for 5 minutes, then carefully invert the pan to turn out the muffins. 7. Dip the muffins in the 3 tablespoons of melted butter until evenly coated. Then roll each muffin in sugar.