8 Tbs. unsalted butter, melted and cooled slightly
2 large eggs
1 tsp. vanilla extract
1½ cups finely diced rhubarb
Directions
Heat the oven to 400°F. Line a 12-cup muffin tin with baking cups.
In a large mixing bowl, combine the flour, sugar, baking powder, cinnamon, baking soda, and salt and whisk to blend.
In a medium bowl, whisk together the sour cream, melted butter, eggs, and vanilla until smooth. Lightly stir the sour cream mixture into the dry ingredients with a spatula until the batter just comes together; do not overmix. Gently stir in the diced rhubarb. The batter will be thick.
Divide the batter among the muffin cups, using the back of a spoon or a small spatula to settle the batter into the cups. The batter should mound a bit higher than the tops of the cups.
Bake the muffins until they’re golden brown, spring back most of the way when gently pressed, and a pick inserted in the center comes out clean, 18 to 22 minutes.