I had this dish in a restaurant in Riga that served good honest local food; they are very keen on their mushrooms in Latvia and the local market was full of produce that had been foraged locally and was a fraction of the price we pay in the UK. This is a great veggie version of a shepherd's pie and you can vary the mushrooms according to what's around.
1 onion, peeled, halved and finely chopped
4 cloves of garlic, peeled and crushed
50g plain flour
750ml hot vegetable stock
400g ceps, cleaned and quartered or cut into 1cm slices
50ml double cream
2tbsp chopped parsley
Salt and freshly ground black pepper
4 servings of mashed potato, mixed with butter and seasoned
4tbsp fresh white breadcrumbs
1tbsp freshly grated Parmesan
Gently cook the onions and garlic in 60g of the butter for 2-3 minutes until soft, stir in the flour then gradually stir in the vegetable stock a little at a time to avoid lumps forming. Season and simmer for about 30 minutes until the sauce has thickened; add a little more stock if it's too thick or continue simmering. The sauce should be thick enough to just bind the ceps once added.
Meanwhile, melt the rest of the butter in a frying pan and fry the ceps on a high heat for a couple of minutes until they are lightly coloured (you may need to do this in two or three batches depending on the size of your frying pan) then mix with the sauce, cream and parsley and season to taste.
Preheat oven to 200C/gas mark 6.
Spoon the mix into pie dishes and either pipe or spoon the potato on top. Bake for 20 minutes, then mix the breadcrumbs and Parmesan and scatter on top; return to the oven for another 10-15 minutes, or until golden.