Instructions

1. Prepare the oven: Preheat oven to 375°F (190°C). Line a muffin tin with paper liners or grease well.
2. Mix dry ingredients: In a bowl, whisk together flour, baking powder, baking soda, salt, and cinnamon.
3. Cream butter and sugar: In another bowl, beat butter and sugar until light and fluffy.
4. Add eggs one at a time, mixing well after each addition. Stir in vanilla extract.
5. Mix in sour cream until smooth and creamy.
6. Combine: Gradually add dry ingredients to wet mixture and stir until just combined.
7. Fold in chopped rhubarb gently.
8. Fill muffin cups: Divide batter evenly into muffin tin cups, filling about 3/4 full.
9. Sprinkle cinnamon sugar topping over each muffin if desired.
10. Bake: Bake for 18–22 minutes or until a toothpick inserted in the center comes out clean.
11. Let muffins cool in the pan for 5 minutes, then transfer to a wire rack.