Heat 10- to 12-inch ovenproof skillet over medium heat; add 1 tablespoon of the butter. Add 2 sliced peaches, and sprinkle with brown sugar. Cook 3 minutes; stir peaches, and cook another 2 to 3 minutes or until caramelized and soft. Remove from the heat; add 1 teaspoon of the vanilla. Toss well, then remove and slide the peaches onto a plate. Rub remaining 1 tablespoon butter in warm skillet. Let skillet cool.
In medium bowl, add Bisquick mix, 2/3 cup whipping cream, eggs and 1 teaspoon vanilla. Mix to combine, being careful not to overmix. Fold in caramelized peaches.
Pour batter into buttered skillet (you can use a greased 13x9-inch pan, if you prefer). At this point, cover the skillet and place in the fridge overnight, or go on to baking step.
The next morning (or whenever you are ready to go on to the baking step), heat oven to 450°F.
Bake at 450°F for 10 minutes, then reduce oven temperature to 350°F, and continue baking 10 to 15 minutes or until lightly golden on top.
Meanwhile, beat 1 cup whipping cream with electric mixer on high speed until soft peaks form. Add powdered sugar and 1 teaspoon vanilla, and whip until combined.
Cut into wedges, and serve hot with sliced peaches, a dollop of whipped cream and a drizzle of maple syrup.