There are many variations on this theme; this is one of the best (and easiest!)

1 (19.9 ounce) package chewy fudge brownie mix
3 ounces tofutti cream cheese
1 cup creamy peanut butter
2 tablespoons soy milk or nondairy creamer
1 egg yolk
1 (16 ounce) can chocolate frosting
Chopped peanuts for garnish (optional)

Preheat oven to 350 degrees. Prepare brownie mix according to package directions. Grease the bottom only of a 9 x 13-inch pan and spread batter in pan. Beat together the tofutti cream cheese, ½ cup peanut butter, soy milk and egg yolk. Carefully spread over batter. Bake for ½ hour. Cool on wire rack for 1 hour. Stir together frosting and remaining ½ cup peanut butter. Spread over cooled brownies. Sprinkle with chopped peanuts if desired.