Add olive oil and just as the oil begins to smoke add the roast to the pan and brown on all sides, seasoning with salt and pepper.
Add the onions, carrots and celery to skillet and stir to coat in oil; let vegetables cook for 3 minutes.
Add the brandy and the beef stock and bring mixture to boil; add the thyme and bay leaf; cover.
Reduce heat to simmer and cook for 2 hours; add the mushrooms and potatoes and cook for another 45 minutes.
Remove the beef from pan and let it rest on cutting board, tented with foil; with a slotted spoon remove the vegetables and place in a serving bowl; increase the heat and reduce the sauce to desired consistency; if you want a thicker gravy cook 1 tbsp butter and 1 tbsp flour together in a small saucepan.
Pour the liquid from the skillet into saucepan and whisk vigoroulsy; season with salt and pepper to taste.