Combine first 3 ingredients in a medium bowl. Combine 2 mashed bananas and next 4 ingredients; add to dry ingredients, stirring with a wire whisk until moistened. Stir in 1/4 cup pecans.
Cook in a preheated, oiled waffle iron until golden.
Meanwhile, melt butter in a large skillet over medium-high heat; add brown sugar and 2/3 cup pecans. Cook, stirring often, 3 minutes or until bubbly. Add 6 bananas; cook 3 minutes or until bananas are tender. Remove from heat.
Heat rum in a small saucepan over medium heat until warm (do not boil). Pour rum over banana mixture, and immediately ignite with a long match. Let flames die down. Return to heat; simmer 4 minutes or until sauce is thickened. Stir in vanilla.
To serve, place 2 banana slices on each waffle; top with vanilla ice cream. Drizzle 2 tablespoons rum mixture over ice cream. Serve immediately.
*For testing purposes only, we used Bisquick Original All-Purpose Baking Mix.