MAKE THE CARAMELIZED ONIONS:
In a skillet on medium-low heat (stainless steel skillets are the best for this recipe), add the olive oil, when hot add the onions. Do not stir until the onion bottoms are dark golden, then stir them and let them cook for at least 1 and a half hours, for perfect results, cook for 3 hours, in both cases, stirring occasionally. When the onions are ready, add the balsamic vinegar, adjust the salt, and set aside.
MAKE THE BRUSSEL SPROUTS:
Wash the Brussel sprouts, remove the ugly leaves, the stem and cut them in half, then add them to boiling water with a pinch of salt, let them cook for 2 minutes. Remove from the water, add them to a bowl with water and ice and let them sit there for 2 minutes. That's the blanching.
SAUTÉ THE BRUSSEL SPROUTS:
Remove the Brussel sprouts from the icy bath and pat them dry
In a skillet on medium heat, add the vegan butter, when hot, add the Brussels sprouts, add salt and pepper, sauté them for about 5 to 6 minutes, or until they are dark brown.
Add the orange zest, the balsamic vinegar, the orange juice, the cranberries, the chestnuts, the caramelized onions and sauté for 1 minute more.
Add the Brussel sprouts to a serving plate, add some more orange zests and voilá! Bon apétit!