Plantain and Steak Tostones

Ingredients (13)

• 6 tablespoons olive oil, divided
• 1/2 large onion, thinly sliced
• 3 cloves garlic, finely chopped
• 3 ounces skirt steak
• 1 teaspoon salt, plus more to taste
• 1 teaspoon pepper, plus more to taste
• 1 teaspoon cumin
• 1 green plantain
• 2 to 3 slices provolone cheese
• 1 tablespoon ketchup
• 1 tablespoon mayonnaise
• Lettuce, optional, for garnish
• Tomato, optional, for garnish