After four years of top-secret development under code name "Project Frisbee," Vlasic Foods International plans to grow its 32% market share in the $850 million retail pickle category with a huge new product. Huge -- as in a pickle slice large enough to cover an entire hamburger. The new three-and-a-half-inch diameter Vlasic Hamburger Stackers, forecasted to generate at least $20 million in annual sales, use 16-inch-long cucumbers cultivated for size, taste, and crunch. Vlasic started developing them after the whopping success of its Sandwich Stackers sandwich-sized pickles. "Hamburger Stackers" are part of Vlasic's drive to increase pickle consumption with sandwiches eaten at home. Only 3% of the 35 billion sandwiches that are eaten at home are served with a pickle, the largest segment being hamburgers. Yet overall, two of every three pickles are eaten with a sandwich. The new pickles will hit supermarkets nationally starting in March. They'll come in 24-ounce wide-mouth jars, with suggested retail of $2.99.