Turn up the heat on the stove to a medium-low flame and put in the 1 teaspoon of olive oil for a couple of minutes maximum. Then once the pan is heated, throw in the onions and crush the garlic into the pan (using a garlic press, or by using the flat side of your knife). Once some of the onions have turned slightly brown, add the sliced mushrooms and stir for a minute, then prepare your next lot of ingredients for adding into the pan in a little while. Keep stirring the mushrooms every few minutes to make sure that they don't stick to the pan or burn.
Prepare the next lot of ingredients: open your 500g of beef mince and separate into 4/6 parts so that it's easier to stir, and prepare the 1 small glass of red wine as well.
Once the mushrooms have browned a little then add the beef mince to the pan and stir. After the mince has been separated from its larger self in the pan, add the red wine so that the mince can absorb the flavour. Cook until the mince has browned.
Prepare your final ingredients for the pan: open the tins of chopped tomatoes and tomato puree and leave the oregano and bay leaf next to them so you don't lose them.
Once you have done this, add water to a large pan and put it on a high heat until it boils.
Once the mince has browned, add the final ingredients for the sauce in this order: chopped tomatoes, tomato purée, oregano and bay leaf. Once these are in, stir thoroughly.
Leave to simmer on a lower temperature, or move it to another, smaller part of the stove over a low heat.
Once the water is boiled, which it should be at this time, add the spaghetti and keep stirring every few minutes to make sure they don't stick, then leave to cook for 10 minutes or until tender with a bite at the centre.
Rinse the spaghetti out into a colander and then rinse with hot water and place in bowls and add the Bolognese on top and you are ready to serve!
Leave mince in a plastic bowl and cover the top in cling-film.