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Keto Herb-Crusted Rack of Lamb with Roasted Garlic Mash

Keto herb-crusted rack of lamb with mashed potatoes plated together with sauce.

Sometimes, we just want to feel a little fancy—without breaking our macros or spending hours in the kitchen. This Herb-Crusted Rack of Lamb with Roasted Garlic Mash delivers that upscale, restaurant-quality vibe while staying completely keto. It's the kind of dish that feels indulgent but is surprisingly simple to pull off, especially if you’ve got a good meat thermometer and a few pantry herbs on hand.

This recipe came together one weekend when we were celebrating a small win—nothing huge, just one of those good days where cooking something a little extra felt right. We wanted something elegant, rich, and comforting that still aligned with our keto lifestyle. The result was a beautifully seared and oven-roasted rack of lamb, crusted with a mix of fresh herbs and Dijon mustard, paired with a creamy roasted garlic cauliflower mash that totally hits those steakhouse side dish cravings.

It’s savory, garlicky, and packed with flavor from start to finish. We love this one for holidays, date nights, or any night we want to take things up a notch—without any carb crashes in sight.

Courses , ,
Difficulty Intermediate
Time
Prep Time: 15 mins Cook Time: 25 mins Rest Time: 15 mins Total Time: 55 mins
Servings 4
Calories 560
Description

Elegant and satisfying, this keto rack of lamb is coated in herbs and Dijon mustard, then oven-roasted to tender perfection. Served with roasted garlic cauliflower mash for a low-carb twist on a steakhouse classic.

Ingredients
    For the Rack of Lamb:
  • 1 rack of lamb (about 1 1/2 to 2 lbs)
  • 2 tablespoons Dijon mustard
  • 2 tablespoons olive oil
  • 1 tablespoon fresh rosemary, finely chopped
  • 1 tablespoon fresh thyme, finely chopped
  • 1 teaspoon garlic powder
  • 1 teaspoon salt
  • 1/2 teaspoon black pepper
  • For the Roasted Garlic Cauliflower Mash:
  • 1 medium head cauliflower, chopped into florets
  • 1 whole head garlic
  • 2 tablespoons olive oil
  • 2 tablespoons butter
  • 2 tablespoons heavy cream (or more, to taste)
  • Salt & pepper to taste
  • 1/4 Optional: cup grated Parmesan for extra richness
Instructions
    Step 1: Roast the Garlic
  1. Preheat the oven to 400°F. Slice the top off the head of garlic, drizzle with olive oil, wrap in foil, and roast for 30–35 minutes until soft and golden. (You can do this while prepping everything else.)
  2. Step 2: Prep the Lamb
  3. Pat the rack of lamb dry with paper towels. In a small bowl, mix Dijon mustard, olive oil, rosemary, thyme, garlic powder, salt, and pepper. Rub the mixture all over the lamb and set aside to marinate briefly.
  4. Step 3: Roast the Lamb
  5. Place the lamb on a rack in a roasting pan or cast iron skillet, bone side down. Roast at 400°F for 20–25 minutes for medium-rare, or longer for your desired doneness. Use a meat thermometer to check for 125°F internal temp (for medium-rare). Remove from oven, tent with foil, and let rest for 10 minutes before slicing.
  6. Step 4: Make the Cauliflower Mash
  7. While the lamb rests, steam or boil the cauliflower florets until fork-tender (about 10 minutes). Drain well and let sit uncovered to release excess moisture.
  8. In a food processor, combine the cauliflower, roasted garlic cloves (squeeze them out of the skin), butter, cream, salt, and pepper. Blend until smooth and creamy. Add Parmesan if using, and pulse again.
  9. Step 5: Plate and Serve
  10. Slice the rested lamb between the ribs and serve over a generous scoop of roasted garlic cauliflower mash. Garnish with extra herbs if desired.

Nutrition Facts

Servings: 4 ServingCalories:560kcalTotal Fat:42gSaturated Fat: 16gTotal Carbohydrate:7gDietary Fiber: 3gSugars: 2gProtein:38g

Note

Substitutions & Variations

  • No Dairy? Use ghee instead of butter and skip the cream or use coconut cream for a dairy-free version.
  • No Dijon? Use stone-ground mustard or a blend of olive oil and minced garlic.
  • Herb Swap: Use parsley or oregano if you don’t have rosemary or thyme.
  • Different Protein: Try this same crust technique on chicken thighs or a pork tenderloin.