Keto Brussels Sprouts Gratin
⏲ ~34 min total · prep 16 · cook 18 · 4 servings
Sides⏱ 45 min total🔥 5.0g net carbs⚡ ≈247 kcal/serving~16% of calories from carbs
By the KFI Test Kitchen · Tested & approved by Jason Lieu, KFI recipe editor
Published Sep 15, 2026 · Updated Sep 15, 2026
Ingredients
- 1 1/2 lb Brussels sprouts, trimmed and halved
- 3 tbsp butter, divided
- 3/4 cup heavy cream
- 4 oz cream cheese, cubed
- 1 cup shredded Gruyère cheese, divided
- 1/2 cup freshly grated Parmesan
- 2 cloves garlic, minced
- 1/4 tsp freshly grated nutmeg
- 1/3 cup pork panko (pulverized pork rinds)
- 3/4 tsp kosher salt
- 1/4 tsp black pepper
Instructions
- Bring a large pot of salted water to a boil, drop in the Brussels sprouts, and blanch 4 minutes; drain well and pat dry.
- Melt 2 tbsp of the butter in a 10-inch cast-iron skillet over medium-high heat, set the sprouts in cut-side down, and sear undisturbed 3 minutes until the cut faces are deeply browned.
- Drop the heat to medium, push the sprouts to the sides, and melt the last 1 tbsp butter in the bare center; add the garlic and cook 30 seconds until fragrant.
- Stir in the heavy cream, cream cheese, nutmeg, salt, and pepper along with half the Gruyère; simmer 3-4 minutes, stirring, until the sauce is thick enough to coat the sprouts.
- Level the sprouts into an even layer and scatter the remaining Gruyère, all the Parmesan, and the pork panko over the top.
- Bake at 400°F for 12-15 minutes, until the edges bubble and the topping is spotty brown; finish 1-2 minutes under the broiler for extra color if you like.
Why this recipe works
- Blanched, then seared Four minutes in boiling water cooks the cores through, and 3 minutes cut-side down in butter builds a brown crust. Skip either one and you get raw centers or no color.
- Half the cheese in the sauce Cream cheese and half the Gruyère melt into the cream to coat every sprout, while the rest goes on top to brown. Sauce-only gratins slide off the vegetables.
- Pork panko crust Pulverized pork rinds scatter over the top and toast into a craggy lid. It replaces breadcrumbs at a fraction of the carbohydrate.
Tips for making this recipe well
Dry the sprouts after blanching
Water on the cut faces blocks browning. Pat the blanched halves with a towel before they meet the hot skillet.
Leave them alone for 3 minutes
Cut-side down, undisturbed, in the butter. Peek early and you lift off pale faces; wait and they come up deep brown.
Simmer the sauce until it coats
Three to four minutes of stirring is enough for the cream cheese to vanish and the sauce to thicken. It should cling to a sprout, not pool around it.
Mind the broiler
One to two minutes adds real color, but panko goes from gold to black fast. Stand at the door with the light on.
Cast iron goes the distance
The skillet goes from burner to oven in one piece, then straight to the table. Set a towel under it when you serve; the handle stays hot long after.
Serving suggestions
Bring the skillet to the table as is, set on a folded towel, and let people scrape from the edge where the crust is thickest. This gratin sits comfortably beside roast chicken or glazed ham, and it earns its place on a holiday table without apology. A sharp salad with vinaigrette cuts the cream, so put one on the table with it.
Storage and meal prep
Refrigerate leftovers right in the skillet, covered, for 3 to 4 days. Reheat in a 350°F oven until bubbling at the edges so the panko crust crisps again; the microwave softens the topping into the sauce. Scoop what you want out instead of reheating the whole pan, since repeated warming dulls the crust. Freezing is not recommended; cream sauces separate when thawed and the sprouts turn olive and soft.
Variations worth trying
- Bacon under the crust Scatter 3 strips of crumbled bacon over the sprouts before the cheese and panko go on. Smoky and rich in the same pan.
- Thyme in the cream Drop a sprig of fresh thyme into the simmering sauce and fish it out before topping. The flavor stays behind after the stem leaves.
- Cheddar instead of Gruyère Sharp cheddar melts in the same way and turns the dish homier. Keep the nutmeg; it does more work than you would expect.
- Halved recipe Make it in a smaller skillet with half of everything. Watch for bubbling edges rather than the clock.
Frequently asked questions
Can I use frozen Brussels sprouts?
Thaw them fully and dry them well, then skip the blanch. Expect less browning on the cut faces; frozen sprouts release water as they cook.
Why blanch if the gratin bakes afterward?
The 4-minute boil cooks the dense cores while the bake only has 12 to 15 minutes. Without it, the centers stay firm and the topping burns while you wait.
Is the broiler step required?
No. The 400°F bake browns the topping on its own; the broiler is there if you want darker, spottier color in the last 2 minutes.
Can I assemble it ahead?
Blanch and sear the sprouts, then refrigerate them separately from the topping for up to a day. Warm the sprouts and sauce in the skillet, add the topping, and bake when you are ready.
How many net carbs per serving?
5.0 net carbs, nearly all from the Brussels sprouts themselves. The cream, cheeses, and pork panko add only a small amount.
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