Keto Garlic Shrimp Au Gratin

This Keto Garlic Shrimp Au Gratin is a luxurious, low carb twist on a classic French bistro favorite, featuring juicy shrimp and tender cauliflower baked in a velvety garlic cream sauce topped with a crisp, golden cheese crust. Heavy cream, Parmesan, and Gruyère create a rich, gratin-style sauce without flour or breadcrumbs, keeping the dish fully keto while still delivering maximum comfort. Serve it as a cozy weeknight dinner, an elegant main for guests, or a light lunch paired with a fresh green salad.

Course Dinner, Lunch, Main Course

Cuisine French, Keto, Low Carb

Keyword au gratin, cauliflower gratin, garlic shrimp, keto shrimp, low carb dinner

Prep Time 15

Cook Time 25

Total Time 40

Servings servings

Calories 420kcal

Equipment

large skillet
medium saucepan
Mixing bowl
9 inch baking dish
oven broiler
Whisk
Colander

Ingredients

For the cauliflower and shrimp base

1 pound large shrimp, peeled and deveined patted very dry
1 medium head cauliflower, cut into small florets
2 tablespoons unsalted butter
1 tablespoon olive oil
3 cloves garlic, minced
1/4 teaspoon crushed red pepper flakes optional, for heat
1 teaspoon kosher salt divided, plus more to taste
1/2 teaspoon black pepper divided, freshly ground

For the garlic cream sauce

1 cup heavy whipping cream
1/2 cup chicken broth low sodium
3/4 cup freshly grated Parmesan cheese divided
1 cup grated Gruyère cheese divided
1/4 teaspoon onion powder
1/8 teaspoon ground nutmeg optional, traditional in gratins

For finishing

1 tablespoon fresh parsley, chopped for garnish

Instructions

Preheat the oven to 400°F and position a rack in the upper third of the oven for broiling later.
Bring a large pot of salted water to a boil, add the cauliflower florets, and cook until just tender but still slightly crisp, about 4 to 5 minutes, then drain well in a colander and let steam off excess moisture.
Pat the shrimp very dry with paper towels, season them with about half of the salt and half of the black pepper, and set them aside while you prepare the skillet.
Heat the butter and olive oil in a large skillet over medium heat, add the minced garlic and red pepper flakes, and cook just until fragrant, about 30 seconds, being careful not to brown the garlic.
Add the seasoned shrimp to the skillet in an even layer and cook, stirring once or twice, until they are just turning pink on the outside, about 2 to 3 minutes, then transfer them with any pan juices to a bowl and set aside, leaving any browned bits in the skillet.
Pour the chicken broth into the same skillet, scraping up any browned bits, then stir in the heavy cream, onion powder, nutmeg, and the remaining salt and black pepper and bring the mixture to a gentle simmer over medium heat.
Whisk in about 1/2 cup of the Parmesan and 1/2 cup of the Gruyère until fully melted and the sauce is thickened enough to coat the back of a spoon, reducing the heat as needed to maintain a gentle simmer without boiling hard.
Taste the garlic cream sauce and adjust the seasoning with additional salt or pepper if needed, keeping in mind that the cheeses are naturally salty.
Add the drained cauliflower and the partially cooked shrimp with their juices to the skillet, gently folding everything together until the shrimp and florets are evenly coated in the creamy sauce.
Transfer the creamy shrimp and cauliflower mixture to a lightly greased 9 inch baking dish, spreading it into an even layer so the gratin browns uniformly on top.
In a small bowl combine the remaining Parmesan and Gruyère, then sprinkle the cheese mixture evenly over the top of the gratin to create a thick, even layer for a golden crust.
Bake the gratin at 400°F until the edges are bubbling and the cheese is melted, about 10 minutes, then switch the oven to broil and broil for 2 to 3 minutes, watching closely, until the top is deeply golden and crisp in spots.
Remove the baking dish from the oven and let the gratin rest for 5 minutes to thicken slightly, then sprinkle with chopped fresh parsley before serving hot.

Notes

For the best texture, do not overcook the shrimp in the skillet since they will finish cooking in the oven. Make sure the cauliflower is well drained and not waterlogged so the cream sauce stays thick and velvety instead of thin. If preparing ahead, assemble the gratin up to the point of adding the cheese topping, cover tightly, and refrigerate for up to 24 hours, then bake an extra 5 minutes before broiling to heat through. Leftovers can be stored in an airtight container in the refrigerator for up to 3 days and are best reheated in a 350°F oven until warmed and bubbly.

Nutrition