reasonable handful of spaghetti
1-2 cloves of garlic, crushed then peeled
¼ leek (the white bit only), sliced
big handful of mushrooms, sliced
1 bacon stock cube
3 tbls-ish sour cream
1 egg, lightly beaten
Put a large pot of water onto boil for the pasta (pop the pasta in when boiling, and cook as per packet directions).
Heat a little butter and oil in a pan. The oil stops the butter from burning – the butter makes everything taste nice! Crush the garlic with the flat blade of your knife, and then peel – it's so much easier. Pop this in the melted butter/oil, and add the leek. Cook the leek it softens a bit, and then add the mushrooms. At this point you can add your favourite herbs – go lightly, parsley is nice. I add one bacon stock cube as a salt substitute, then fish out the garlic, and turn the heat off while the pasta finishes cooking.
When the pasta's ready, turn the heat under the frying pan onto low, stir through the mustard, then add the pasta. Don't completely drain the pasta – a little water will help to thin out the cream. With the heat still low, add the cream and mix it through – the sour cream might take a while to warm up and liquefy. Turn the heat off to add the egg so you don't scramble it, and stir it through. Serve immediately.
Measurements are intentionally vague to facilitate one's ability to play with one's food.