Courgette Gratin with Lactose-Free Milk

Name: Courgette Gratin with Lactose-Free Milk
Prep time: 45 min
Ingredients: 800g courgettes (around 3 medium, preferably unpeeled); 250ml lactose-free milk; 3 eggs; 80g grated aged hard cheese (such as Comté or Gruyère, naturally low in lactose); 2 tablespoons extra virgin olive oil; 1 teaspoon dried thyme; 1 teaspoon dried basil; 1 small bunch of fresh chives (or 2 tablespoons finely snipped); ½ teaspoon salt; ¼ teaspoon freshly ground black pepper; 1 pinch of ground nutmeg; 1 tablespoon olive oil (for greasing the dish)

A light, meltingly tender gut-friendly gratin: lactose-free, IBS-adapted and packed with easy-to-digest vegetables to nurture your microbiome.

45 min Easy Published on May 23, 2026

Ingredients

800g courgettes (around 3 medium, preferably unpeeled)
250ml lactose-free milk
3 eggs
80g grated aged hard cheese (such as Comté or Gruyère, naturally low in lactose)
2 tablespoons extra virgin olive oil
1 teaspoon dried thyme
1 teaspoon dried basil
1 small bunch of fresh chives (or 2 tablespoons finely snipped)
½ teaspoon salt
¼ teaspoon freshly ground black pepper
1 pinch of ground nutmeg
1 tablespoon olive oil (for greasing the dish)

Instructions

Preparation Steps

Preheat your oven to 180°C (fan). Lightly grease a gratin dish approximately 25 x 20 cm with the tablespoon of olive oil set aside for this purpose.
Prepare the courgettes: wash them thoroughly, then slice into rounds approximately 4–5mm thick. There's no need to peel them — the skin provides extra fibre and carotenoids, and is perfectly well tolerated once cooked.
Draw out excess moisture to prevent a watery gratin: place the slices in a colander, sprinkle with a pinch of salt, toss gently and leave to rest for 15 minutes. Pat them dry carefully with kitchen paper or a clean tea towel. This step improves the final texture and concentrates the flavour.
Lightly pre-cook the courgettes: heat 2 tablespoons of olive oil in a large frying pan over a medium heat. Add the drained courgette rounds and sauté for 5–7 minutes, stirring regularly, until lightly golden and tender but still holding their shape. Add the thyme, basil and black pepper. Remove from the heat.
Make the egg custard: crack the 3 eggs into a large bowl and beat with a fork. Pour in the lactose-free milk, add the nutmeg and a pinch of salt, then mix until smooth. Stir in half the grated cheese and the snipped chives. Mix again to combine.
Assemble the gratin: arrange the pre-cooked courgette rounds in even layers in the greased gratin dish. Pour the egg and milk mixture evenly over the top, making sure it seeps well between the slices. Finish by scattering the remaining grated cheese over the surface.
Bake for 25–30 minutes, until the top is golden and lightly gratinéed and the custard is fully set (it should no longer be liquid in the centre — check by gently tilting the dish). If the surface browns too quickly, cover loosely with a sheet of aluminium foil halfway through cooking.
Leave to rest for 5 minutes out of the oven before serving. This resting time allows the gratin to firm up and the flavours to settle. Serve warm, alongside a green salad or steamed rice as you prefer.

Gut-Friendly Tips & Variations

🌿 Strictly Low-FODMAP Version

Make sure your aged cheese is a hard variety (Comté, Gruyère, Parmesan): these contain very little residual lactose and are generally well tolerated even without a "lactose-free" label.
Avoid any seasoning containing garlic or onion powder: always read the labels on spice blends carefully.
Replace the chives with the green tops of spring onions if you'd like a slightly more pronounced flavour whilst remaining low-FODMAP.
Be mindful of your courgette portion: approximately 65g of cooked courgette per serving is considered low-FODMAP. Beyond this, tolerance varies from person to person. Listen to your body.

🧀 Fully Dairy-Free Variation

Replace the lactose-free milk with an unsweetened, FODMAP-friendly plant-based drink (plain rice milk or oat milk without added inulin, in a small quantity according to your tolerance).
Replace the cheese with nutritional yeast (1–2 tablespoons) for a satisfying, savoury gratin effect along with a boost of B vitamins.

🍳 Why This Recipe Is Gentle on Your Gut

Well-cooked courgettes are amongst the easiest vegetables to digest, being high in water and low in FODMAPs in reasonable portions.
Lactose-free milk retains all the calcium and protein of regular milk without triggering excessive fermentation in those with lactase deficiency.
Eggs provide complete protein without fermentable fibres, making them an excellent binding ingredient for a digestively comfortable dish.
Extra virgin olive oil contributes polyphenols associated with greater microbiome diversity as part of a Mediterranean-style diet.
By avoiding garlic and onion, the recipe becomes naturally suited to low-FODMAP elimination phases whilst remaining full of flavour thanks to the aromatic herbs.