Wash the cauliflower and cut it into smaller pieces (including the stem). Add the florets to the bowl of a food processor. Pulse several times.
Finely mince the onion with a knife or in a food chopper. Sauté the onion in olive oil with cloves, peppercorns and juniper berries.
Add the cauliflower rice to the pot and sauté over medium-high heat until slightly golden. Stir frequently to prevent it from sticking to the bottom of the pot.
Add in the tomato sauce, tomato paste, tamari, sugar, bouillon powder, a pinch of salt and the bay leaf (or bouquet garni). Give it a good stir.
Simmer the cauliflower spaghetti sauce with a lid on for 15 minutes or up to 1 hour over low heat.