1. Lay the bacon on parchment paper-lined baking sheets.
2. Preheat oven 205°C/400°F, baked for 5 minutes, discard the excess fat and cool the bacon. Then cut in very small pieces, using a food processor.
3. Set a large pot on high heat. Add the butter, shallots and onions to the pot.
4. Cooked until they are caramelized and add the vinegar, maple syrup, brown sugar, thyme and some freshly ground pepper. Bring to a boil and reduce for 15 minutes.
5. Add the cooked bacon pieces and simmer until the liquid has evaporated, stirring constantly.