I love muffins, don't you? And cupcakes. Really fine line there. What is it I read once about the difference? Cupcakes have frosting, whereas muffins do not. That's a good enough explanation for me. But if you want a formulaic definition, here it is, courtesy of Diana's Desserts:
"A basic formula for muffins is 2 cups flour, 2-4 tablespoons sugar, 2½ teaspoons baking powder, ½ teaspoon salt, 1 egg, ¼ cup oil, shortening or butter and 1 cup milk. When the fat, sugar and egg ratio in a recipe reaches double or more than this, you have reached the cake level."
But the first definition says it all. Muffins never have frosting. Does the cinnamon sugar on top of mine count as frosting? :) And just to make these a bit more unusual, I added a touch of cardamom. Of course, these are rhubarb muffins. Did I forget to mention that? They are a little tart, a little sweet...a great combination. And incredibly tender. Just a tad of butter needed....or maybe not. I passed on the butter and scarfed them down warm right out of the oven
9 oz. (2 cups) all-purpose flour
3/4 cup granulated sugar
2-1/2 tsp. baking powder
1 tsp. ground cinnamon
1/2 tsp. baking soda
1/2 tsp. kosher salt
1 cup sour cream
4 oz. (8 Tbs.) unsalted butter, melted and cooled slightly
2 large eggs
1 tsp. pure vanilla extract
1-1/2 cups 1/4-inch-diced rhubarb (7-1/4 oz.)
For the topping:
3 Tbs. granulated sugar
1/2 tsp. ground cinnamon
(I added 1/4 teaspoon cardamom)
Position a rack in the center of the oven and heat the oven to 400°F. Line a 12-cup muffin tin with paper or foil baking cups.
Make the muffin batter: 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.
Make the topping: In a small bowl, combine the sugar and cinnamon and mix well. Sprinkle a generous 1/2 tsp. of the cinnamon-sugar mixture over each muffin.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. Transfer to a rack and let the muffins cool in the pan for 5 to 10 minutes. Carefully lift the muffins out of the pan—if necessary, loosen them with the tip of a paring knife—and let them cool somewhat. Serve warm.
Yields 12 medium muffins.