Peanut Butter Brownies

0 Preheat the oven to 350F
1 Grease a 13 x 9-inch pan (line with parchment if desired)
2 Whisk cooled melted butter, sugar, eggs, and vanilla together in a large mixing bowl until smooth.
3 Blend the dry ingredients together in a medium mixing bowl.
4 Stir in the dry ingredients into the egg mixture until well blended but do not over beat.
5 Fold in the M & Ms, reserving about 1/4 cup to sprinkle on top.
6 Spoon into the prepared pan and smooth the top.
7 Place the peanut butter in a small mixing bowl. Make sure it's microwave safe.
8 Warm it for a few seconds, just until it is soft enough to spread easily.
9 Spoon it in thick lines across the brownies.
10 Use a spoon to swirl it through the brownie batter - don't overmix.
11 Sprinkle with the remaining 1/4 cup M&Ms.
12 Bake at 350F for 25 to 30 minutes, or until done but still soft in the middle.