Warm, bakery-soft cinnamon muffins with a sparkly cinnamon-sugar top. Made from pantry staples, these mix-and-bake muffins are perfect for breakfast, brunch, school lunches, or make-ahead snacks—and they freeze beautifully.
Preheat the oven to 375°F (190°C). Line a 12-cup muffin pan with paper liners or grease lightly.
In a large bowl, whisk together flour, granulated sugar, brown sugar, baking powder, salt, cinnamon, and nutmeg (if using).
In a medium bowl, whisk milk, melted butter, eggs, and vanilla until smooth.
Pour the wet ingredients into the dry ingredients and fold gently with a spatula just until the last streak of flour disappears; do not overmix.
Divide the batter evenly among the muffin cups, filling each about two-thirds to three-quarters full.
In a small bowl, mix the topping sugar and cinnamon. Sprinkle over each muffin.
Bake 15–18 minutes (18–22 minutes if cups are fuller) until the tops spring back and a toothpick inserted into the center comes out clean or with a few moist crumbs.
Cool in the pan for 5 minutes, then transfer muffins to a wire rack to cool completely. Serve warm or at room temperature.