Orange muffins with Brown Sugar Glaze

I got this recipe from "the pioneer woman cooks" website. Really yummy!

1 c. sugar
1 c. butter, softened
2 eggs
1 c. buttermilk (if you don't have buttermilk, add 1 T. vinegar to 1 c. milk)
1 t. baking soda
2 c. sifted flour
grated rind of 2 oranges
juice of 2 oranges
1 c. brown sugar

Preheat oven to 375 degrees. Cream butter and sugar together. Add eggs and mix well. Dissolve baking soda into buttermilk; pour in mixing bowl. Add 2 c. flour and orange rind and mix together well. Fill mini muffin pans (regular ones work, too) 2/3 full and bake for 12-17 minutes, until light golden. Remove from oven.

Combine 1 c. brown sugar with the juice from the 2 oranges. Stir together, and drizzle over warm muffins. Remove from pans immediately and eat warm.