Rhubarb Muffins

2 1/2 cups flour
1 teaspoon baking soda
1/2 teaspoon salt
1 1/4 cups packed brown sugar
1 egg
1/2 cup melted butter
1 cup buttermilk
1 teaspoon vanilla
2 cups chopped rhubarb

Topping:
1/2 cup packed brown sugar
1 tablespoon melted butter
1/2 teaspoon cinnamon

In a medium bowl combine flour, baking soda, salt and sugar.

In another bowl, beat the egg, stir in butter, buttermilk and vanilla.

Make a well in the dry ingredients, and add the egg mixture all at once. Stir until just blended and stir in the rhubarb.

Spoon into greased or paper lined muffin tins.

Topping:
Combine sugar, butter and cinnamon. Sprinkle a spoonful of topping over each muffin.
Bake at 350 degrees for 20 to 25 minutes.