4 oz UNSALTED butter
2 oz Unsweetened chocolate
2 c  All-purpose flour
1 ts Baking soda
1/4 ts Salt
1 c  Buttermilk, at room
-temperature
1 c  Packed dark brown sugar
1    Egg, lightly beaten
1 ts Vanilla extract
6 oz Milk chocolate, cut into
-1/4" to 1/2" pieces
6 oz Bittersweet chocolate, cut
-into 1/4" to 1/2" pieces
1 c  Toasted walnuts, coarsely
-chopped (*)

(*) Place the walnuts in a single layer on a baking sheet and bake at 400
degrees for about 5 minutes, shaking the sheet a couple of times. Preheat
oven to 400 degrees. Lightly butter twelve 3-by-1 1/4 inch muffin cups.

In a medium saucepan, over low heat, melt the butter and unsweetened
chocolate. Remove the pan from the heat and cool the mixture until tepid.
In a large bowl, stir together the flour, baking soda and salt. In another
bowl, stir together the buttermilk and brown sugar until smooth. Then stir
in the chocolate/butter mixture, egg and vanilla until combined. Make a
well in the center of the flour mixture. Add the liquid ingredients and
stir just to combine. Stir in the chocolates and walnuts.

Spoon the batter evenly among the prepared muffin cups. Bake 19 to 22
minutes, or until a cake tester or toothpick inserted into the center of
one muffin comes out with a few crumbs remaining. Remove the muffin tin or
tins to a wire rack. Cool the muffins in the pan(s) for 5 minutes. Remove
the muffins from the cups and finish cooling on the rack. Serve warm or
cool completely. Store the muffins in an airtight container at room
temperature. Makes about 12 muffins.