Veggie-Stuffed Steak Rolls

INGREDIENTS

1 tbsp

oil, plus more for searing

1/2

red bell pepper, thinly sliced

1/2

yellow bell pepper

1/2

white onion, thinly sliced

1/2 tsp

salt, plus more seasoning

1/2 tsp

black pepper, plus more for seasoning

3 cloves

garlic, minced

2 lb

flank steak, flattened as much as possible

1 1/2 cups

spinach

1/3 cup

shredded mozzarella cheese

Long toothpicks or short skewers