In a small saucepan, boil the heavy cream until thickened. Add the white pepper and lemon juice; remove from heat and set aside. In a medium skillet, sauté the onions in olive oil until they begin to brown.
Roll out the pizza dough and place onto a non-stick pizza pan. Sprinkle on the cheese, then prosciutto. Add the cream mixture a little at a time to the pizza (Tablespoons full) forming little puddles spread around the pizza. Drain the onions and put them on last. They will continue to caramelize as the pizza bakes.
Bake 8 to 12 minutes. Don't overbake. You don't want to "dry-out" the pizza. Slice and eat!