This is a great do-ahead dish that is a real crowd pleaser. The soft leeks and potatoes can be cooked ahead of time and the salmon marinated, so all you need to do is pop the whole tray in the oven to finish cooking when guests arrive.
2 Tbsp olive oil
25g butter
2 leeks, thinly sliced
2 cloves garlic, sliced
1 sprig rosemary leaves, very finely chopped
1kg waxy potatoes, cut into 5mm slices
1 Tbsp wholegrain mustard
2 Tbsp maple syrup or liquid honey
2 tsp white miso
2 tsp soy sauce
1 side salmon
125ml white wine
125ml chicken or fish stock
2 Tbsp chives, finely chopped
In a large frying pan, heat the oil and butter and add the leeks, garlic, and rosemary. Season with salt and pepper and cook over a gentle heat until very soft.
Meanwhile, put the potatoes in a pan of cold, salted water and bring up to a boil. Simmer for 5-8 minutes, or until the potatoes are just tender. Drain well and add to the pan with the leeks. Toss together and spread onto a large, lipped roasting dish. This can be done a day ahead.
To make the glaze for the salmon, mix the wholegrain mustard together with the maple syrup, miso, and soy sauce. Brush the mix over the salmon at least 30 minutes before cooking, but ideally overnight.
When you’re nearly ready to cook, heat the oven to 200°C.
Add the white wine and stock to the leeks and potatoes and cook for 20 minutes. Remove from the oven and lay the salmon on top of the vegetables. Return to the oven and bake for 15-20 minutes, or until cooked to your liking. Allow to rest for 5 minutes before slicing. Scatter with chives to serve.