01 -
Preheat the oven to 400°F. Line a 12-cup muffin tin with paper or foil baking cups.
02 -
In a medium mixing bowl, combine the flour, sugar, baking powder, ground cinnamon, baking soda, and salt, and whisk to blend.
03 -
In a large bowl, whisk together the Greek yogurt, melted butter, eggs, and vanilla until smooth.
04 -
Add the dry ingredients to the wet ingredients and lightly stir with a spatula until the batter just comes together; do not overmix. Gently stir in the diced rhubarb.
05 -
Evenly divide the batter among the muffin cups. The batter should mound slightly higher than the tops of the cups.
06 -
In a small bowl, mix together the sugar and cinnamon for the topping. Sprinkle ½ teaspoon of the mixture over each muffin and gently pat into the tops of the muffins.
07 -
Bake the muffins until golden brown and a toothpick inserted into the center comes out clean, about 20-22 minutes.
08 -
Let the muffins cool in the pan for 5-10 minutes, then transfer them to a wire rack to cool completely. Best served warm.