Carrot "Yofi Falafel" Lettuce Cups

Finely slice your onion. Ready a pot or pan that has a lid and place it on medium heat. Add a drizzle of olive oil, a knob of butter and your onion. Season well and stir to coat. Cover with a lid and allow to simmer, stirring occasionally and adding a drizzle of water when/if required. After 5 minutes, add 2 tablespoons of balsamic vinegar, turn down the heat to low and allow the onions to caramelize further with the lid on. Check every now and then to see they are not burning and add further water as needed. This should take 12-15 minutes in total.