FOUND IT: In a Penzey's catalog.
These are easy, good and fairly healthy.
1 stick butter
1 1/4 cup sugar (or Splenda)
1 1/4 cups cooked, mashed sweet potatoes, about one good sized potato (see microwave note below)
1/3 cup milk
1 1/2 cups flour
2 tsp baking powder
1/4 tsp salt
1 tsp cinnamon
1/4 tsp ground nutmeg
1/2 cup raisins
1/4 cup chopped pecans (optional)
Topping (I skipped this):
2 tbsp sugar
1/4 tsp cinnamon
Cream the butter with the sugar, then add eggs one at a time. Stir in the sweet potatoes and the milk. In a separate bowl, combine the flour, baking powder, salt, cinnamon and nutmeg. Combine the two mixtures, stirring until moistened. Fold in the raisins and pecans. Spoon into greased muffin tin (or silicon liners). Fill to about 2/3 of capacity. Sprinkle topping on if you're using it, then bake at 375 for 25-27 minutes.
To microwave sweet potato, wash it off, poke some holes in it with a fork, wrap it in plastic wrap and microwave for 8-10 minutes.