Double Fudge Muffins

Oh, these muffins are wonderful. This recipe goes back to one of my old Bon Appetit magazines, 25 years ago to be exact. The writer of the recipe called it a dessert muffin, but we don't think that way in our family. A muffin is for breakfast or brunch in our house, but these are rich and are saved for special times. This recipe is easy, but does take a little longer to make than most muffin recipes. I serve them with fruit, some form of eggs, and a breakfast meat for a terrific Saturday or Sunday brunch. 
Recipe:

5 ounces semisweet chocolate chips (if you don't have a scale, this is a scant cup, or just between 3/4 cup and 1 cup.)
2 ounces unsweetened baking chocolate (2 squares)
1/3 cup butter
3/4 cup low-fat sour cream
2/3 cup firmly packed brown sugar
1/4 cup light corn syrup
1 large egg, room temp.
1-1/4 teaspoons vanilla
1-1/2 cups unbleached all-purpose flour
1 teaspoon baking soda
1/4 teaspoon salt
1 cup semisweet chocolate chips

1. Preheat oven to 400 degrees. Generously grease 16 2-1/2" muffin cups or line with foil baking cups.
2. Melt first 3 ingredients together in a double boiler set over barely simmering water. Stir until smooth. Remove chocolate from over water to cool slightly.
3. Whisk the sugar into the chocolate. Add sour cream, corn syrup, egg and vanilla and whisk until combined.
4. Mix dry ingredients together in a large bowl. Mix in the chocolate chips.
5. Make a well in the center of the dry ingredients. Add chocolate mixture to well; stir into dry ingredients until just blended (batter will be lumpy).
6. Spoon batter into prepared cups, filling each 3/4 full.
7. Bake muffins until tester inserted in center comes out moist and almost clean, about 20 minutes. Cool 5 minutes. Remove from pan and serve warm.

Serves 16
Tip: If you don't have a double boiler, the chocolate and butter can be melted in the microwave. Be careful to heat and stir slowly so as not to burn the chocolate. Also, the foil baking cups work so much better than greasing the muffin pan. Much less mess and the muffins to not stick to the cups with this recipe.