I found this recipe in Self magazine adapted from a spa in Arizona. It's delicious! I added powdered sugar on top and ate it with ice cream (Mom added milk, but that's gross).
1 1/2cupsbrown sugar
3ozunsweetened, bittersweet, or semisweet chocolate, melted
1 1/2cupsall-purpose flour
1 1/2teaspoonbaking soda
1 1/2teaspoonspure vanilla extract
Vegetable oil cooking spray
Heat oven to 350˚. Beat sugar and butter in a bowl until combined. Beat in eggs, then chocolate, then sour cream. Sift flour and baking soda in a bowl; add to chocolate mixture. Beat in coffee, vanilla and salt until combined. Coat a 9" x 13" pan with cooking spray; pour in batter. Bake until a toothpick inserted in center comes out clean, 35 minutes.
279 calories per slice, 11 g fat (6 g saturated), 42 g carbs, 2 g fiber, 4 g protein