1Heat oven to 350º. Lightly grease bottom only of rectangular pan, 13x9x2 inches, with shortening or spray bottom with cooking spray.
2Stir Bisquick mix, oats, brown sugar, butter and egg in large bowl until well blended. Press on bottom of pan. Bake 16 to 18 minutes or until golden brown.
3Place white baking chips and whipping cream in small microwavable bowl. Microwave uncovered on Medium-High (70%) 1 minute; stir. Microwave 10 to 15 seconds longer or until mixture can be stirred smooth. Spread over baked layer. Sprinkle with nuts; press gently into topping. Cool completely, about 1 hour. For bars, cut into 8 rows by 4 rows.