Heat a medium-large stock pot or Dutch oven with the olive oil over
low heat. Add in the onion, carrot, celery and mushrooms and cook for
about 5 minutes, stirring often, until the veggies have softened.
Add in the beans and lentils, then pour in the wine. Stir all the ingredients
together for 2 minutes.
Stir in the tomato paste followed by the bay leaf, then pour the stock into
the pot, bring to a gentle boil and simmer for 15 to 20 minutes over low heat.
In the meantime, fill two-thirds of a large stockpot with water and bring to
a boil. As soon as the water boils, add roughly 1 tablespoon (15 g) of fine
sea salt, fold in the spaghetti and cook until al dente, about 7 to 8 minutes.
Discard the bay leaf from the Bolognese sauce and season with ¼ teaspoon
(or to taste) of sea salt and freshly cracked black pepper to taste. Drain
the pasta and transfer it into the pot with the sauce. Stir to combine all the
ingredients, then divide the pasta between the plates and serve.