Made this last night. just cut the peach into 4ths, cooked in the sauce not grilled separately. used 1 1/4 oz bourbon, 1 oz dark rum, 1/2 oz peach schnapps, 2 TB of butter and 2 TB brown sugar, made plenty of sauce for one peach. Throw the pecans in to get coated with the sauce, then top with whipped cream and shovel into your facehole. Would be good with a scoop of icecream too, but I had none. Poor me.
Original post, with pretty pictures: http://www.fifteenspatulas.com/grilled-peaches-with-bourbon-brown-butter-sauce/
My version: slice a peach into 4 parts. Melt butter in small frying pan, add brown sugar and booze. Stir until melted and brown, then add peach. Cook 1-2 minutes on each side. Add the pecans when you turn the peach slices. Be careful not to allow the alcohol to ignite, it will cook off on its own, no need to flambee down the house.
Use a bigger pan and scale recipe accordingly to serve more than one at a time.