One-Pan Ancho Pork Tenderloin - Our Favorite Easy Family Dinner by Marie Saba

Ingredients

• 2 teaspoons ancho chili powder
• 2 teaspoons brown sugar
• 1 teaspoon dried oregano
• 1 teaspoon salt
• 1 teaspoon lime zest
• 1 pork tenderloin (about 1.5 lbs.)
• Extra virgin olive oil
• 1/2 large sweet onion, sliced into thin half-rings
• 1/2 large red bell pepper, sliced into thin strips
• Salt and pepper
• 1 tablespoon butter (optional)