Preheat grill then lower temp to medium-high

Heat olive oil in a large sauté pan over medium heat

Saute onions until they begin to soften, then stir in spinach and cook until wilted and soft

Add bread crumbs, feta cheese, seasonings and sun-dried tomato pesto

Cook for 1-2 minutes more until mixture is heated through and well incorporated

Set aside

Grill steaks 6-8 minutes per side for medium-rare, this depends on the thickness of your steak, so use a meat thermometer to check for doneness

Medium-rare steaks should be 125 degrees F, 130 for medium

Preheat the oven broiler and top the cooked steaks with the spinach mixture

Broil, watching carefully, until topping is heated and just starting to turn lightly golden brown on top

Serve immediately