Keto Garlic Butter Beef Tenderloin
A showstopping low-carb centerpiece, this Keto Garlic Butter Beef Tenderloin features a tender, perfectly roasted beef tenderloin finished with a rich garlic-herb compound butter — restaurant-quality flavor with simple, keto-friendly ingredients.
Ingredients
- 2½ lb 1.13 kg beef tenderloin, trimmed and tied (center-cut whole roast)
- Kosher salt and freshly ground black pepper
- 1 –2 tbsp avocado oil or olive oil for searing
- Garlic Butter compound butter
- 8 tablespoons 113 g unsalted butter, softened
- 3 –4 garlic cloves finely grated or minced (about 2 tbsp)
- 1 tbsp fresh parsley finely chopped
- 1 tsp fresh thyme leaves chopped (or ½ tsp dried thyme)
- 1 tsp lemon zest optional
- Sea salt and freshly ground black pepper to taste
- Optional for basting
- 2 tbsp unsalted butter
- 2 garlic cloves smashed
- 2 –3 sprigs fresh rosemary or thyme
Instructions
- Trim & tie (if necessary). Trim any silver skin and excess fat. If the tenderloin tapers, fold the thin end under and tie the roast at 1–1.5″ intervals so it cooks evenly.
- Make the garlic butter. In a small bowl, combine the softened butter, grated garlic, chopped parsley, thyme, lemon zest (if using), and a pinch of salt and pepper. Mix until smooth. You may form into a log and chill or leave soft for immediate use.
- Dry brine & rest. Pat the roast dry. Generously season all over with kosher salt and a light grind of black pepper. For best flavor and texture, salt the roast 30–60 minutes before cooking or up to 24 hours in advance (refrigerate uncovered if doing long dry brine). Remove from fridge ~30–45 minutes before cooking to come toward room temperature.
- Choose your cooking method. (Reverse sear recommended for even medium-rare.)
- Reverse sear (recommended): Preheat oven to 225°F (107°C). Place roast on a rack set in a rimmed sheet pan. Roast until internal temperature reaches 115–120°F (46–49°C) for a final target of 125–130°F (52–54°C) medium-rare (about 35–60 minutes depending on size). Remove and tent.
- Sear-then-roast (classic): Preheat oven to 425°F (220°C). Heat a heavy skillet until very hot. Sear roast in oil 2 minutes per side to brown. Transfer to oven and roast until internal temp is 125–130°F (52–54°C) (typically 12–18 minutes; check with thermometer).
- Sous-vide (precision): Season and vacuum-seal roast; cook at 129°F (54°C) for 1.5–3 hours, then pat dry and sear 30–60 seconds per side.
- Sear & baste (finish). If reverse searing: heat a heavy skillet (cast iron) over high heat with 1–2 tbsp oil until just smoking. Sear roast quickly on all sides to form a crust (30–60 seconds per side). In the last 20–45 seconds, add 2 tbsp butter, smashed garlic and herb sprigs to the pan and spoon the foaming butter over the roast (baste) for flavor and sheen.
- Top with garlic butter & rest. Transfer roast to a cutting board, top with slices or a pat of the compound garlic butter so it begins to melt. Tent loosely with foil and rest 8–12 minutes (resting allows juices to redistribute and carryover heat to reach final doneness).
- Carve & serve. Remove twine. Slice roast into ½–1″ slices against the grain. Arrange on a warm platter, spoon any pan juices and melted garlic butter over the slices, and garnish with a sprinkle of chopped parsley and a twig of thyme or rosemary.
Notes
- Don’t skip the thermometer. Internal temperature is the most reliable guide: 125–130°F (52–54°C) for medium-rare. Aim a few degrees below your target when removing from heat to allow for carryover.
- Dry brine for better crust and deeper flavor. Salt the roast 1–24 hours before cooking and refrigerate uncovered if possible.
- Make-ahead: Compound garlic butter can be made up to 5 days ahead (refrigerated) or frozen for longer. The butter also makes a great finishing touch on other steaks or roasted vegetables.
- Storage: Refrigerate leftovers in an airtight container up to 3–4 days. Freeze (vacuum-sealed or tightly wrapped) up to 3 months.
- Reheating: Warm gently in a 250°F oven until just warmed through (avoid high heat that dries the meat). A short sear after warming refreshes the crust.
- Variations: Wrap with bacon for added fat, mix blue cheese into the compound butter, or press an almond-flour herb crust on before searing for texture.
- Keto tip: Serve with buttery cauliflower mash, sautéed mushrooms, or roasted asparagus to keep the plate low-carb and satisfying.