Here is an awesome, intensely chocolate cookie that I've made for years. It
comes from the Bon Appetit Christmas book (page 13). I always double the
batch as they are quite popular!

Chocolate Rads
(makes about 15)

1 pound bittersweet (not unsweetened) or semisweet chocolate
1 3/4 cups sugar
4 large eggs
1/4 cup (1/2 stick) unsalted butter, melted
1 tablespoon vanilla extract
1 teaspoon instant espresso powder or instant coffee powder
1/2 cup cake flour
1 teaspoon baking powder
1/4 teaspoon salt
2 1/3 cups semisweet chocolate chips (about 14 oz)
1 cup chopped walnuts, toasted (about 4 oz) (I always add more chocolate
here and omit the nuts)

Melt chocolate in top of double boiler over simmering water, stirring until
smooth. Remove from heat. Using electric mixer, beat sugar and eggs in
large bowl until pale yellow and thick, about 5 minutes. Beat in melted
chocolate, melted butter, vanilla and espresso powder. Sift flour, baking
powder and salt into small bowl. Stir dry ingredients into chocolate
mixture. Mix in chocolate chips and nuts. Cover and refridgerate mixture
until firm, approximately 30 minutes.

Preheat oven to 350 F. Line 2 large cookie sheets with parchment paper.
Drop batter by 1/2 cupfuls onto prepared cookie sheets, spacing evenly.
Press with moist fingertips to form 3 1/2 - 4 inch rounds. Bake cookies
until tops become dry and crack, about 16 minutes. Cool cookies on
parchment. Remove from parchment. Cover and store in airtight container at
room temperature.