Vegetarian Pirozhki

Onion first, alone in the pan, because onion needs a head start — everything that goes in after it is either wetter (courgette, mushrooms) or tougher (carrot, celery) and would stop the onion from softening properly if they all went in together. You're not browning it hard, just taking it from sharp and raw to sweet and translucent — the colour tells you, not a clock.

Mushrooms chopped very finely matter because mushroom is nearly all water trapped in cell walls; the finer the cut, the faster that water escapes into the pan where you can boil it off, rather than staying locked inside and leaking out later into your dough. The carrot, courgette and celery are grated coarsely instead of chopped for the opposite reason — you want texture to survive the simmer, not vegetable mush. Thirty minutes uncovered is the real engine of this filling: uncovered because a lid traps steam and you'd just be reheating water, not losing it. If after that the pan still looks like soup, raise the heat — don't add more time at a gentle simmer, you'll just overcook the vegetables waiting for water that won't leave at low temperature.

Tomato purée here isn't for acidity so much as body — it gives the filling something to cling to once it's reduced, so it holds together in a spoonful instead of falling apart. Paprika and cumin are the only spices, which tells you this filling is meant to taste of itself, not of a spice cupboard — any single warm spice you like could stand in, but don't stack three or four or you'll lose the vegetables under them.

If, even after the simmer, the filling is still too loose — sieve it. That drained liquid isn't waste, it's vegetable stock, concentrated exactly the way you'd want it for a soup base later. This is just good economics: nothing here with real flavour gets thrown away.

The dough is a milk dough — 300ml milk to 475g flour, enriched with 50g butter and an egg only for the glaze, not inside. Yeast dissolved in room-temperature milk, not warm, not hot: yeast is a living thing and heat above body temperature kills it faster than it feeds it — "some say warm milk wakes the yeast up better" — no, because warm here easily tips into hot in an ordinary kitchen with no thermometer in hand, and dead yeast doesn't rise twice as fast, it just doesn't rise. Room temperature is slower but it's reliable, and reliability beats speed when the alternative is flat pirozhki.

Butter goes in after the first knead, not before, because a dough that's already built some gluten structure can take on fat without the fat coating the flour and stopping gluten forming at all — add butter too early and you get a dough that tears instead of stretching. Ten minutes on medium speed after that is doing real work: this is what makes the final crumb soft rather than dense, and there's no shortcut for it by hand in a home kitchen unless you're prepared to knead far longer than ten minutes and accept it won't be quite as even.

The hour's rise on the counter under a towel is patience as an ingredient, plainly: you can't rush fermentation, and a dough forced to prove in a warm oven "to speed things up" will often overproof unevenly, giving you some pies with big air pockets and others dense. A towel instead of clingfilm is enough — you're stopping a skin forming on top, not sealing anything.

Butter is here for softness and a particular dairy flavour that no oil replicates in enriched dough — if you had none, you'd move toward a plainer bread-like result, which isn't the same pirozhok but isn't a failure either. Olive oil for frying the vegetables, meanwhile, is doing nothing but carrying heat — any neutral oil with no smell of its own does the same job; you'd only reach for a fruity olive oil if you wanted its flavour sitting under the vegetables, which here you don't, since the spices are doing that work.

The second rise, just 15 minutes once shaped, is short on purpose — it's not meant to double the dough again, only to relax it after the stress of rolling and crimping, so the pies don't look taut and tear in the oven. Crimping with a fork after wetting the edge isn't decoration — it's a seal, and a filling this reduced and dry won't leak much even if the seal isn't perfect, which is another reason you cooked the moisture out of it in the first place. Egg wash gives colour and a bit of shine; flaked salt and thyme on top are there because a soft enriched dough, left plain, tastes a little flat on the crust, and a pinch of salt right at the surface wakes it up far more than salt mixed into the dough ever could.