Heat the olive oil and brown the beef well over medium heat (do this in small batches).
Remove each batch of meat once it’s browned and set aside.
Add the onions to the pot (with a little more oil if needed).
Slowly cook, stirring occasionally, until they are translucent and starting to caramelise.
Return the beef to the pan and pour in the dark beer.
Add the stock, brown sugar, cloves, bay leaves, rosemary and thyme.
Spread the mustard on the bread and place the slices, mustard side down, on top of the stew. The bread will melt into the stew during cooking and serve as a thickener.
Reduce the heat to low, place the lid on the pot and simmer for 1-2 hours (until the beef is tender, time will vary slightly depending on the cut of beef).
Check from time to time that the beef is not drying out and add a little more stock or water if needed.
When the beef is nice and tender and the sauce has thickened, turn off the heat and remove the rosemary and thyme stalks and the bay leaves.
Stir in the balsamic vinegar.
Serve with your favourite roasted vegetables, or do as the Belgians do, enjoy with a side of chunky fries.
