Crispy Keto Pork Belly with Caramelized Onions and Herb Butter

By Lauren Mitchell, Test Kitchen Director · Reviewed by AislePrompt Editorial · Published 2026-04-07 · Updated 2026-04-07

A savory, high-fat dish featuring perfectly seared pork belly with a sweet-savory onion glaze and fresh herb butter finish, ideal for keto dieters craving indulgence without the carbs. This american-inspired keto (low-carb) ready in about 40 minutes pairs Pork belly, skin-on, trimmed, Salt, Black pepper for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 650 calories and feeds 4, so it slots cleanly into a low-carb week and pairs well with cauliflower rice or roasted green vegetables. 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.

Ingredients

• 1.5 lbs Pork belly, skin-on, trimmed
• 1 teaspoon Salt
• 1/2 teaspoon Black pepper
• 1 tablespoon Olive oil
• 1 medium Yellow onion
• 2 cloves Garlic
• 1 tablespoon Apple cider vinegar
• 1 teaspoon Fresh thyme
• 1 tablespoon Unsalted butter

Instructions

1. Step 1: Pat the 1.5 lbs pork belly dry with paper towels, then season both sides evenly with 1 teaspoon salt and 1/2 teaspoon black pepper. Heat 1 tablespoon olive oil in a large oven-safe skillet over medium-high heat until shimmering, then place pork belly skin-side down and cook for 8-10 minutes until skin is golden brown and crisp.
2. Step 2: Flip pork belly and cook for 5 minutes to sear the flesh side, then transfer skillet to a preheated oven at 375°F (190°C) and roast for 20 minutes, or until an internal thermometer reads 145°F (63°C).
3. Step 3: While pork roasts, heat a small skillet over medium heat and add the thinly sliced 1 medium yellow onion. Cook for 10-12 minutes, stirring occasionally, until deeply golden and caramelized. Add 2 minced garlic cloves and cook for 1 minute until fragrant, then pour in 1 tablespoon apple cider vinegar and scrape up browned bits from the pan.
4. Step 4: Remove pork from oven and let rest for 5 minutes. Slice into 1/2-inch thick pieces. Return caramelized onion mixture to skillet over medium heat, stir in 1 teaspoon chopped fresh thyme and 1 tablespoon unsalted butter until butter melts and mixture is glossy.
5. Step 5: Serve pork belly topped with caramelized onion mixture and a dollop of herb butter, ensuring every slice is coated for maximum flavor.