Blend the pumpkin, yolks, eggs, syrup, and sour cream in a food processor until very smooth. Stir in the bacon, salt, and pepper.
Coat six -oz. heatproof ramekins with baker's spray and pour in the batter. Place the cups in a roasting pan, add enough hot water to come halfway up the sides of the cups, and bake at 350° for 30 minutes.
Remove from the oven and let the flans rest 20 minutes. Run a blunt knife around the edges of the flans and unmold them onto plates. Top with sour cream and garnish with thin slices of orange zest, if desired. Serve immediately.