This elegant cheesy baked kohlrabi gratin transforms the humble, often overlooked kohlrabi into a sophisticated side dish that rivals the finest potato gratins in richness and flavor. Thinly sliced kohlrabi bulbs are layered with a luxurious cream sauce infused with fresh herbs and garlic, then topped with a generous blend of Gruyère and Parmesan cheeses that melt into a golden, bubbly masterpiece. The kohlrabi’s naturally sweet, turnip-like flavor becomes incredibly tender and creamy during the slow baking process, while maintaining just enough texture to provide substance and interest. Each spoonful delivers layers of comfort – from the silky cream sauce that binds everything together to the crispy, caramelized cheese top that provides textural contrast. This gratin proves that kohlrabi deserves a place at the finest dinner tables, offering a unique twist on classic comfort food that will surprise and delight guests who may have never experienced this versatile vegetable prepared with such care and sophistication.
Serves: 6-8 people
Ingredients You’ll Need
For the kohlrabi base:
- 4-5 large kohlrabi bulbs (about 3 pounds total)
- 2 teaspoons salt for preparation
- 2 tablespoons butter
For the creamy sauce:
- 2 cups heavy cream
- 1/2 cup whole milk
- 3 cloves garlic, minced
- 2 tablespoons fresh thyme leaves (or 2 teaspoons dried)
- 1 tablespoon fresh sage, chopped (or 1 teaspoon dried)
- 1 teaspoon salt
- 1/2 teaspoon white pepper
- 1/4 teaspoon nutmeg, freshly grated
- 2 tablespoons all-purpose flour
For the cheese topping:
- 1 1/2 cups Gruyère cheese, freshly grated
- 1/2 cup Parmesan cheese, freshly grated
- 2 tablespoons fresh chives, chopped for garnish
Selecting and Preparing Kohlrabi
Choose kohlrabi bulbs that are firm, heavy for their size, and free from soft spots or cracks. The skin should be smooth and the attached leaves (if any) should look fresh and green. Smaller to medium bulbs tend to be more tender than very large ones. Remove any leaves and trim the root end, then use a sharp knife or vegetable peeler to remove the tough outer skin completely – this step is crucial as the skin can be quite fibrous.
Creating Perfect Kohlrabi Slices
Using a sharp knife or mandoline slicer, cut the peeled kohlrabi into thin, even slices about 1/8 inch thick. Consistent thickness ensures even cooking throughout the gratin. If using a mandoline, use the hand guard for safety. Place the sliced kohlrabi in a large colander and toss with 2 teaspoons of salt. Let sit for 15-20 minutes to draw out excess moisture, then rinse thoroughly under cold water and pat completely dry with clean kitchen towels.
Preparing Your Baking Dish
Preheat your oven to 375 degrees Fahrenheit. Generously butter a 9×13 inch baking dish or a similar-sized gratin dish. The butter prevents sticking and adds flavor to the bottom layer. If you want extra richness, you can rub the dish with a cut garlic clove before buttering.
Making the Luxurious Cream Sauce
In a medium saucepan over medium heat, combine the heavy cream, milk, minced garlic, thyme, sage, salt, white pepper, and nutmeg. Heat the mixture gently, stirring occasionally, until it just begins to simmer around the edges – don’t let it boil vigorously or it may curdle. Remove from heat and let the herbs infuse the cream for 10 minutes.
In a small bowl, whisk the flour with about 1/4 cup of the warm cream mixture to create a smooth paste. Whisk this paste back into the cream mixture to prevent lumps and help thicken the sauce as it bakes.
Building the Gratin Layers
Arrange half of the kohlrabi slices in an overlapping pattern in your prepared baking dish, like shingles on a roof. This layering technique ensures even coverage and an attractive presentation. Pour half of the cream sauce over this first layer, gently shaking the dish to help the sauce settle between the slices.
Add the remaining kohlrabi slices in another overlapping layer, then pour the rest of the cream sauce over the top. The sauce should come up to just below the top layer of kohlrabi. Gently press down on the layers with a spatula to help compress them slightly and ensure the sauce penetrates throughout.
Adding the Cheese Crown
In a medium bowl, combine the grated Gruyère and Parmesan cheeses, mixing well. Sprinkle this cheese mixture evenly over the top layer of kohlrabi and cream sauce. The cheese should cover the entire surface generously – this will create that beautiful golden, bubbly top that makes gratin so irresistible.
The First Baking Phase
Cover the dish tightly with aluminum foil and bake for 45 minutes. This covered cooking allows the kohlrabi to steam and become tender while the flavors meld together. The cream should be gently bubbling around the edges when you check it.
Creating the Golden Finish
Remove the foil and continue baking for another 25-30 minutes, or until the top is golden brown and bubbly, and a knife inserted into the center meets little resistance. The kohlrabi should be completely tender, and the cream sauce should be thickened and bubbling actively around the edges. If the top isn’t browning enough, you can run it under the broiler for 2-3 minutes at the very end.
Testing for Perfect Doneness
The gratin is ready when the top is beautifully golden and the kohlrabi layers yield easily to a fork. The cream sauce should be thickened but still creamy, not dried out or separated. If you insert a knife into the center, it should slide through all layers with minimal resistance.
The Essential Resting Period
Remove the gratin from the oven and let it rest for 10-15 minutes before serving. This resting time allows the cream sauce to set up slightly, making it easier to serve neat portions. The surface will continue to bubble gently during this time as the gratin settles.
Serving Your Elegant Creation
Cut the gratin into generous squares and serve with a large spoon to get through all the layers. Each portion should have golden, cheesy top, creamy middle layers, and tender kohlrabi throughout. Garnish with fresh chopped chives for a pop of color and mild onion flavor that complements the rich, creamy base.
Perfect Pairing Suggestions
This sophisticated gratin pairs beautifully with roasted meats like beef tenderloin, pork loin, or roasted chicken. It also makes an excellent vegetarian main course when served alongside a crisp green salad and crusty bread. The rich, creamy nature of the dish calls for bright, acidic accompaniments like a simple vinaigrette or pickled vegetables.
Make-Ahead and Storage Tips
This gratin can be assembled up to a day ahead and refrigerated before the final baking. Add an extra 10-15 minutes to the covered cooking time if baking from cold. Leftover gratin keeps well in the refrigerator for up to 4 days and reheats nicely in a 350-degree oven until warmed through. The flavors actually develop and improve after a day, making leftovers almost as good as the original.
