Pre-heat the oven to 375 degrees F.

Slice the red onion into rings.

Heat the olive oil in small saucepan over medium-high heat until hot.

Add the red onion and cook about 5 minutes or until crisp-tender, stirring often

Stir in the sugar and apple cider vinegar to the saucepan. Reduce the heat to low and cook 5-10 minutes or until most of liquid has evaporated, stirring occasionally.

Pound the chicken cutlets flat between two pieces of plastic wrap.

Sprinkle both sides with Italian seasoning.

Grill or pan fry the chicken about 5 minutes on each side, or until browned and juices run clear. (If pan frying, drain off any excess liquid.)

In a small bowl, combine the mayonnaise and minced garlic.

Spread each sandwich roll with the mayonnaise mixture.

Layer each sandwich roll bottom with baby spinach leaves, followed by the cooked chicken,  the red onion sauce mixture,  the provolone cheese slices, and the top halves of the buns.

Bake 5 minutes in the pre-heated oven.