Pumpkin Pecan Muffins

This is a recipe from Taste of Home.

2 1/2 C. flour ( I use 1/2 whole wheat)
1/2 C. sugar
1/4 C. packed brown sugar
2 tsp. pumpkin pie spice
1 tsp. baking powder
1 tsp. baking soda
1/2 tsp. salt
2 eggs
1 C. canned pumpkin
1/2 C. buttermilk (add 1 tsp. lemon juice to milk to substitute)
1/4 C. Canola oil
1 tsp. vanilla
1/2 C. chopped pecans
1/2 C. mini chocolate chips (not in original recipe)
Crumb Topping:
1/3 C. packed brown sugar
1/3 C. finely chopped pecans
1/4 C. flour
1/4 c. cold butter

In a large bowl, combine the first seven ingredients. In another bowl, whisk the eggs, pumpkin, buttermilk, oil and vanilla. Stir into dry ingredients just until moistened. Fold in pecans. Fill six greased jumbo muffin tins 3/4 full. Do not over fill!
In a small bowl, combine the brown sugar, pecans and flour. Cut butter in until crumbly. Sprinkle over batter. This is the best part of the muffins!
Bake at 375˚ for 25-30 minutes or until a toothpick comes out clean. Serve warm. Yield: 6 Jumbo muffins or 12 regular muffins.