Preheat oven to 400 degrees F (200 degrees C) and place a grill pan in the oven. (Or preheat countertop induction oven on medium heat with grill pan inside.)
Bring balsamic vinegar to a boil in a saucepan; reduce heat and simmer until balsamic is reduced and thickened into a glaze, 10 to 15 minutes.
Pound pork cutlets with a mallet to about 1/2-inch thickness.
Cook and stir sausage, onion, and jalapeno in a skillet over medium heat until onion slightly translucent and sausage is cooked through, about 5 minutes. Add peaches and apple; cook and stir filling until fruit is softened, about 5 more minutes. Add about 1 tablespoon balsamic glaze to the top and stir.
Spoon filling into the center of each pork cutlet, reserving leftover filling in the skillet. Roll up culet and tie with roasting twine. Place rolled pork onto heated grill pan and return to oven.
Bake in the preheated oven, turning pork halfway through, until pork is cooked through and browned on the outside, 20 to 25 minutes. (Or grill on medium heat in the countertop induction oven for 15 minutes (7 1/2 minutes each side.)
Pour balsamic glaze over leftover filling in the skillet; cook and stir over low heat just until warm. Spoon filling onto cooked stuffed pork.