For the Sticky Sweet Caramel Sauce: Melt butter in a large saucepan over medium-low heat. Stir in brown sugar and cook, stirring occasionally until sugar is dissolved. Whisking gently, stir in whipping cream. Simmer for 5-8 minutes or until sauce has thickened.
Remove caramel sauce from heat and stir in bar-b-q sauce. Allow caramel sauce to cool slightly and serve as desired or cool completely and store a glass jar in the refrigerator for up to two weeks. Note: Refrigerated sauce can be reheated uncovered in 30 second increments in the microwave.
For the Grilled Peach Sundaes: Preheat an outdoor grill or indoor grill pan to medium-high heat and oil grill grates. Using a pastry brush, brush the cut sides of the peaches with melted butter.
Place peaches cut side down on preheated grill. Grill peaches for 5-6 minutes or until flesh is slightly charred and peaches are tender.
Remove peaches from grill and set aside to cool slightly. Top each peach with a large scoop of ice cream, a generous drizzle of prepared Sticky Sweet Caramel Sauce, 1-2 tablespoons toasted pecans, 1-2 tablespoons cookie crumbs, a dollop of whipped cream and a cherry. Serve immediately.