Gluten-Free Double Chocolate Brownies

6 eggs
1 cup granulated sugar
1 cup brown sugar
2 tablespoons vanilla extract
6 (1 ounce) squares semisweet chocolate
12 ounces semisweet chocolate mini morsels,
    divided into 2 (6 ounce) portions
1 pound (4 sticks) butter
1 cup gluten-free flour
1 teaspoon salt
1/2 teaspoon xanthan gum (available at health food stores)
1 1/2 cups chopped walnuts

Heat oven to 350 degrees F. Grease a 12 x 18-inch cake pan.

In large bowl, mix eggs, sugars and vanilla extract.

In a double boiler, melt the chocolate squares, half the chocolate morsels and the butter, then add to the egg and sugar mixture.

Sift together the gluten-free flour, salt and xanthan gum; stir into the mixture. Stir in the remaining chocolate morsels and walnuts. Spoon into the prepared pan and bake for 30 minutes. Cool and cut into squares.