In a large saucepan over medium heat, combine cream and butter. Bring mixture to a simmer, stirring constantly. Remove pan from heat. Add semisweet and milk chocolate morsels. Stir until melted and smooth. Cool slightly. Transfer to a fondue pot, chafing dish, or ceramic bowl. Serve immediately with sliced apples, sliced bananas, strawberries, cookies, pretzels, and pound cake.