Midwestern-Style Pork Tenderloin Sandwich with Caramelized Onion

By AislePrompt Test Kitchen · Reviewed by AislePrompt Editorial · ·

Juicy pork tenderloin grilled and layered with sweet caramelized onions on a toasted bun, capturing the hearty flavors of the Midwest region. This american-inspired sandwiches & wraps ready in about 40 minutes pairs salt, black pepper, olive oil for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 480 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Prep: 15 min Cook: 25 min Serves 4 American cuisine 480 cal/serving
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Ingredients

Instructions

  1. Step 1: Season 1 lb pork tenderloin medallions evenly with 1 tsp salt and 1/2 tsp black pepper. Heat 1 tbsp olive oil in a grill pan over medium-high heat and grill pork slices for 3-4 minutes per side until nicely browned and internal temperature reaches 145°F. Remove and rest.
  2. Step 2: While pork cooks, melt 1 tbsp butter with 1 tbsp olive oil in a skillet over medium heat. Add 1 large thinly sliced yellow onion and cook slowly, stirring occasionally, for 15-20 minutes until golden brown and caramelized.
  3. Step 3: In a small bowl, mix 1/4 cup mayonnaise, 1 tbsp Dijon mustard, and 1 tbsp ketchup to make a tangy spread.
  4. Step 4: To assemble, spread the sauce evenly on 4 toasted hamburger buns. Layer each with a lettuce leaf, 2-3 pork medallions, caramelized onions, and 2 tomato slices. Serve immediately.

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Frequently asked questions

How long does Midwestern-Style Pork Tenderloin Sandwich with Caramelized Onion take to make?

Total time is about 40 minutes (15 min prep + 25 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.

How do I store leftover Midwestern-Style Pork Tenderloin Sandwich with Caramelized Onion?

Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep salt from drying out.

Can I substitute ingredients in Midwestern-Style Pork Tenderloin Sandwich with Caramelized Onion?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale Midwestern-Style Pork Tenderloin Sandwich with Caramelized Onion for a different number of people?

The recipe is written for 4 servings. Multiply each ingredient by (your serving target / 4). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

What goes well with Midwestern-Style Pork Tenderloin Sandwich with Caramelized Onion?

American sandwiches & wraps like this pair well with a simple grain (rice, couscous, or crusty bread), a quick salad with acid (lemon vinaigrette, pickled onions), and a pan sauce or yogurt-based dip. Tap "Plan a meal with the AI" to get specific side suggestions.

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