Rhubarb Muffins - cooking recipe

Ingredients

1 1/2 cups unbleached flour or 1 1/2 cups whole wheat flour
1 cup whole wheat flour
1 teaspoon baking soda
1 teaspoon baking powder
1/2 teaspoon salt
1 1 cup sour milk or 1 cup plain yogurt
3/4 cup brown sugar
1/2 cup oil
1 egg, beaten
2 teaspoons vanilla
1 1/2 cups fresh rhubarb, diced
1/2 cup nuts, toasted and chopped (optional)
1/4 cup sugar
1 tablespoon butter, melted
1 teaspoon ground cinnamon
1 teaspoon flour

Preparation

In a mixing bowl, combine the two flours, baking soda, baking powder and salt (first 5 ingredients).
I another bowl, combine the buttermilk, brown sugar, oil, egg and vanilla, mixing thoroughly (next 5 ingredients).
Stir in dry ingredients until just moistened.
Stir in rhubarb and nuts (if using).
Fill greased or paper-lined muffin tins two-thirds full.
Combine final 4 ingredients and sprinkle on top of batter.
Preheat oven to 375F and bake until toothpick inserted in center comes out clean (about 20 minutes).
Remove from pans and cool on wire racks.