adapted from: Sally's Baking Addiction
6 oz. low-fat or fat-free vanilla yogurt (I used plain)
1/4 c. skim milk
1 egg
1/4 tsp. salt
1 tsp. baking powder
1 c. sugar (or Splenda)
1/2 c. unsweetened cocoa powder
1/2 c. old-fashioned rolled oats (not quick cooking)
3/4 c. creamy peanut butter
Add all the ingredients to a blender, except the peanut butter, adding the wet first to help it mix easier. Blend until smooth and oats are ground. Stopping to scrape once or twice. Pour into a lightly greased 8x8 baking dish. Microwave peanut butter for 30 seconds. Drop spoonfuls over brownie batter and swirl with a knife, creating a marble look. Bake at 350 degrees for 25-30 minutes or until they pull away from the pan. They will be extra fudgy, so make sure to wait until completely cooled before cutting.