Keeping a supermarket pizza in the freezer is fine for emergencies, but if your pizza choices are like those in my supermarket — thin-crusted and skimpy on the cheese and meat — you’re getting more of a snack than a meal. Buy an inexpensive pizza for this recipe. Check the directions and choose the brand that bakes the fastest. Then heap the crust with barbecued chicken and cheese for a mouthwatering meal. Serve salad on the side.