Instructions

1. 1

   Preheat the oven to 375°F and line a 12-cup muffin pan with paper liners or lightly grease the pan. The muffins rise best when the oven is fully heated before the batter goes in.

2. 2

   In a large bowl, whisk together the flour, baking powder, baking soda, salt, brown sugar, and cinnamon until the brown sugar is evenly broken up with no large clumps left.

3. 3

   In a separate bowl, whisk the eggs, melted butter, buttermilk, and vanilla until smooth and creamy. The mixture should look glossy and fully combined.

4. 4

   Pour the wet ingredients into the dry ingredients and stir gently just until a few flour streaks remain. Fold in the chopped rhubarb carefully so the batter stays light instead of dense.

5. 5

   Divide the batter evenly between the muffin cups, filling each about three-quarters full. Sprinkle the tops with the cinnamon sugar topping if using.

6. 6

   Bake for 18 to 22 minutes, until the tops are lightly domed and golden brown around the edges. A toothpick inserted into the center should come out with a few soft crumbs but no wet batter.

7. 7

   Let the rhubarb muffins cool in the pan for about 5 minutes before moving them to a wire rack. The centers finish setting as they cool.