Kohlrabi, spinach & smoked mackerel gratin

Ingredients

• 800-900g kohlrabi
• 2 smoked mackerel fillets (150g)
• 200g spinach (large leafed)
• 300ml double cream
• 100ml whole milk
• Juice of ½ lemon
• 4 tsp wholegrain mustard
• White pepper

Method

Pre-heat the oven to 220C. Dig out a medium-sized gratin or oven-proof dish – I use a 23cm circular pan, which is about 7cm deep.

Cut any stalks off the kohlrabi and reserve the leaves. Peel with a vegetable peeler, then use a mandolin to slice into 3mm-thick pieces. Put to one side.

Wash the spinach thoroughly, remove and discard the stalks and chop the leaves in half. Put the cream, milk, 1 tsp mustard and a good pinch each of salt and white pepper in a milk pan and warm to a gentle simmer while you assemble the gratin.

Spread the kohlrabi slices in one layer. Smear with 1 tsp mustard. Season with salt and pepper and flake one third of the mackerel over the top. Place a layer of spinach (and the kohlrabi leaves if you have them) over this, then repeat three times, and finish with a fourth and final layer of kohlrabi slices.

Squeeze the lemon juice into the milk pan, then pour this over the kohlrabi. Place on a baking tray (in case the cream bubbles over) and cook in the middle of the oven for 45-50 mins, until the kohlrabi and leaves have released their juices and become tender. The cream should be bubbling round the sides and brown on top.

This makes a lovely supper, served with a crisp, refreshing salad and perhaps some fresh bread to mop up the juices.

Image: Ed Smith