Heat oven to 375°. Spray a 13 x 9 inch glass baking dish with cooking spray.
In a medium bowl, stir Bisquick mix and water until soft dough forms.
Drop half of dough by spoonful evenly in bottom of baking dish (dough will not completely cover bottom of the dish).
Drizzle about 1 cup of pizza sauce over dough.
Arrange ½ of the pepperoni slices evenly over sauce.
Top with 1 cup cheese.
Repeat layers with remaining dough, sauce, pepperoni and cheese.
Bake 20-25 minutes or until golden brown. Cut into squares to serve.
