Kohlrabi, spinach & smoked mackerel gratin

by Ed Smith

Ed Smith makes the most of one of winter’s less-attractive vegetables

The wholegrain mustard and lemon cut through the mellow, earthy flavours of cooked kohlrabi and spinach, while the cream and smoked mackerel add a few more layers of flavour to the dish. This makes a lovely supper, served with a crisp, refreshing salad and perhaps some fresh bread to mop up the juices. 

This recipe came about as part of my article on the hidden charms of kohlrabi—you can read it here.


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
Sea salt and white pepper


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.

Recipe and image: Ed Smith