Cook the pasta according to the packet instructions.
Meanwhile, cut the mushrooms into chunks or slices. Chop the garlic and the chilli pepper, if used.
Heat the oil in a frying pan and gently sauté the garlic, chilli or chilli flakes for a few seconds, then add the mushrooms. After five minutes add a ladleful of the pasta’s cooking water, the lemon juice and the green peas. Put the lid on and steam for 5 minutes. ( If you’re not using Pesto, add the stock powder to the mixture now).
The pasta should be ready by now. Drain it and add to the mushroom and pea mixture. Add 1 Tbsp of vegan pesto, if liked, and stir gently. Add the fresh herb of your choice, season with salt and pepper to taste and add some more lemon juice if needed.
Serve warm, garnished with fresh herbs.