Start by slicing the 1st onion into half rings. Grab a skillet add some oil to the pan and drop in the onions. Let’s them cook for 3 mins over a medium heat. Add in the brown sugar and balsamic vinegar and turn the heat down to low, let them cook slowly for 10-12 minutes until they start to caramelize.
Preheat your oven to 180 degrees C. Place a casserole dish over a medium heat & add a little oil. When the pan is hot add the onions along with the garlic, celery, onions and mushrooms. Sauté the mixture for 2-3 minutes before adding the celeriac & vegan sausages.
For the caramelised onions place a non-stick pan over a medium heat and add a little oil, followed by the finely sliced onions then allow them to sauté for 5 minutes. Add the balsamic, sugar & thyme then cook for a further 10 minutes over a low heat until nicely caramelised.