1 (18.25 ounce) box yellow cake mix
3/4 cup butter
2 1/2 cups quick oats
12 ounces preserves or jam
1 tablespoon water
Preheat oven to 375 degrees F.
Melt butter. Combine cake mix and oats in a large bowl; stir in the melted butter until the mixture is crumbly. Measure half of this mixture (about 3 cups) into a greased 13 x 9-inch pan. Press firmly into pan to cover the bottom.
Combine preserves and water; spoon over crumb mixture in pan, and spread evenly. Cover with remaining crumb mixture. Pat firmly to make top even. Bake for 20 minutes. The top should be very light brown. Cool completely before cutting into bars.