1 c. (2 sticks) butter, softened
1 1/2 c. Quaker oats (quick or old-fashioned uncooked)
1/2 c. all-purpose flour
1 c. firmly packed brown sugar
2 eggs
1 c. chopped walnuts
1 tsp. vanilla extract
1 (12 oz.) pkg. semi-sweet chocolate morsels, divided

In large mixer bowl, mix butter, oats, flour, brown sugar, eggs, walnuts and vanilla. Beat 3 minutes at medium speed or until mixture is light and fluffy. Stir in 1 cup semi-sweet chocolate morsels. Spread batter into 8-inch square microwave-safe baking dish; cover dish with wax paper. Cook on High power 4 minutes; rotate dish 1/4 turn. Cook on High power 4-5 minutes longer or until top of cake appears dry and bottom is an even color.

Sprinkle remaining 1 cup chocolate morsels over top of warm cake. Let stand 10 minutes then spread chocolate evenly over cake. Cool directly on countertop. Cut into serving pieces. Serves 8-12.