Mix first three ingredients together until well blended. Mixture will stick to beaters and resemble cookie dough consistency. Use spatula to smash and spread evenly in ungreased 9 x 13 pan.
Mix last three ingredients on low speed until well blended. Mix on medium speed for about 3 minutes or until mixture is the consistency of cake batter (bubbles should appear in the batter). Pour on top and spread evenly with spatula.
Bake at 350°F on center rack for 45-50 min or until toothpick inserted in center comes out clean. Top will be very golden brown. Cool completely before cutting into 1 to 2 inch squares (to fit in muffin cups).