Method

1. Boil the spaghetti according to packet instructions, omitting any salt.
2. Heat the oil in a pan and add the onion. Stir for 3-4 minutes.
3. Add the garlic and stir for 1-2 minutes.
4. Add the tomatoes and sliced mushrooms and cook gently for about 10 minutes at the lowest heat. 
5. Add the pesto and almonds, stir for 1-2 minutes and remove from the heat.
6. When ready, drain the spaghetti, reserving some of the cooking liquid, and add the spaghetti to the sauce. 
7. Heat everything through again for 5 minutes, adding a little cooking liquid to thin the sauce if required.