Greek-Style Beef Stuffed Portobello Mushrooms

Ingredients

• 1 pound Ground Beef (93% or leaner)
• 4 large portobello mushroom caps, stems removed and chopped
• 1/2 cup diced onion
• 2 tablespoons Greek seasoning
• 1-1/2 teaspoons minced garlic
• 1/8 teaspoon pepper
• 1 package (10 ounces) frozen chopped spinach, thawed, squeezed dry
• 3/4 cup crumbled reduced-sodium feta cheese, divided
• 1 cup diced seeded tomatoes
• 1/4 cup finely diced pitted Kalamata olives
• tzatziki sauce, balsamic glaze, Greek salad dressing, hummus, roasted red pepper strips, diced cucumbers