Leek, Fennel & Spinach Gratin
Leek, Fennel & Spinach Gratin – Oozy, gooey, creamy, cheesy, (slightly) healthy vegetable gratin, who can say no to that? A creamy, cheesy, and utterly irresistible vegetable gratin that makes the perfect comforting side dish. Think soft, fragrant leeks and fennel, sautéed until tender, then folded into a rich and velvety cheesy béchamel sauce. Topped with crispy golden panko breadcrumbs for that perfect crunch, then baked until bubbling and golden—this dish is indulgence with a (slightly) healthy twist!
While it shines as a side dish for roasted meats, festive feasts, or cosy Sunday dinners, this gratin is so satisfying it could easily steal the spotlight as a vegetarian main. The sweetness of leeks and fennel pairs beautifully with the creamy sauce, while spinach adds a fresh, earthy balance. It’s a crowd-pleaser that’ll have everyone coming back for seconds!
Why You’ll Love This Recipe
✔️ Creamy & Cheesy – A rich, velvety béchamel sauce coats every bite.
✔️ Golden & Crispy – Topped with panko breadcrumbs for the perfect crunch.
✔️ Comforting Yet Nutritious – Packed with leeks, fennel, and spinach for a veggie boost.
✔️ Versatile Side or Main – A stunning side dish or a hearty vegetarian meal.
✔️ Make-Ahead Friendly – Assemble in advance and bake when ready.
This oozy, gooey, golden gratin is pure comfort— An amazing side dish if there ever was one!
Inspired by a recipe by The Kitchn. Looking for a more carby gratin side dish? Then try my Cabbage & Potato Gratin or this amazing Roasted Fennel & Sourdough Gratin inspired by BBC Good Food.
Leek, Fennel & Spinach Gratin
(8 votes, average: 4.13 out of 5)
Loading...Ingredients
- 1 tbsp olive oil
- 1 tbsp butter 1 onion, finely chopped
- 2-3 garlic cloves, finely chopped
- 1 leek, rinsed & finely chopped
- 1 fennel, thinly sliced
- 300 g spinach or other leafy green, roughly chopped
- 50 g butter
- 2 tbsp flour
- 500 ml milk
- Grated nutmeg
- ± 75 g parmesan cheese, freshly grated
- Pepper & salt to taste
- ± 50 g panko bread crumbs
- Small bunch parsley, chopped
Instructions
Preheat the oven to 180°C.
In a large heavy based pan heat the olive and add 1 tbsp butter. Add the onions and sauté for 3 minutes until translucent and fragrant. Add the garlic, sauté for another 30 seconds then add the leek and fennel. Give it a good mix so it’s all coated, turn the heat down and put the lid on the pan. Let it slowly steam / sauté on low heat. Stir now and then while you make your sauce.
In a separate heavy based pan add 50 g of butter, when starting to foam, add the flour. Stir well. Keep stirring, it will first turn a very light colour and slowly become more yellow, ± 3 minutes.
Slowly pour in the milk, a small amount at a time, while you keep stirring, using a whisk to get rid of the lumps. Let it bubble away on low heat for ± 10 minutes while you stir now and then. Stick a wooden spoon into the sauce and draw a line with your finger on the back. If the line holds, you’re done. If it flows back you need a bit longer.
When the béchamel sauce is done add the parmesan cheese, grate in a good amount of nutmeg and season with pepper and salt. Taste and adjust to your liking.
Add the béchamel to the vegetable mix, stir to coat. Then mix in the spinach. Transfer the mixture into an oven dish and sprinkle some panko bread crumbs over the top.
Bake in the oven for 20 minutes until bubbly and golden and sprinkle on some parsley.
