Start by soaking the clay pot in cold water for at least 20 minutes, then drain.
Cut the garlic cloves into thin slivers. These will be inserted into the beef for added flavor.
The onion needs to be diced and a bouquet garni needs to be prepared.
The red bell peppers need to be halved lengthwise and seeded. Be sure to remove the ribbing.
You are going to make a thickener with the butter and flour which is called a beurre manie. It is easier to work with when the butter is soft so take out the butter now and let it sit until soft. If you have to heat it up a little in a pan or in the microwave.
Using a paring knife, make a bunch of small incisions throughput the meat and insert the garlic slivers into them.
Season the meat with salt and pepper on all sides.
Heat a large heavy bottomed pan over medium high heat, add the oil and let it get hot. You want the oil to heat up just to the point of smoking. No more.
Now add the beef and brown on all sides. Remove it from the pan and set aside uncovered.
Add the onion to the pan and saute the onions until golden. Remove the onions from the pan and transfer to the clay pot.
Put the beef on top of the onions and get the beef stock ready.You do this by combining the stock, tomato puree and wine together in a bowl and then pour it over the beef in the clay pot. Add the bouquet garni to the clay pot, cover and place in the COLD oven. We don't want to preheat the oven when using a clay pot. Remember, a cold clay pot does not do well with extreme temperature changes.
Crank up the oven to 400° F and cook for 1 hour.
Remove the cover from the clay pot, baste, add the bell pepper halves and continue cooking uncovered for about 45 minutes or until the beef is tender.