Pumpkin Streusel Muffins

My sister T. makes a mean (meaning really nice) pumpkin streusel muffin. The recipe (natch) is from Penzeys.

1/2 c butter, soft
1 c brown sugar
1 egg
1 c pumpkin puree
1/4 c evaporated milk
1 t baking soda
1/2 t salt
1 1/4 t cinnamon
1/4 t ginger
1/8 t cloves
1 2/3 c flour

TOPPING
2 T flour
2 1/2 T sugar
1 t cinnamon
1 T butter, firm

Set oven to 375 F. Grease or line 12 muffin cups. Blend streusel ingredients to the size of small peas. Cream butter with brown sugar. Blend in egg. Mix in pumpkin and milk. Gently stir in spices and soda. Stir in flour-- don't overmix. Portion into cups; distribute streusel. Bake 18-22 minutes.