Preheat the oven to 250.
In a large dutch oven heat the oil and butter until hot but not smoking.
Add the carrots, cook until browned, remove from pot and set aside.
Add the onions, sear until browned, remove from pot, set aside.
Sprinkle with roast on all sides with salt, garlic powder and the flour. Rub the flour in evenly.
Sear in the pan until browned on all sides, remove from the pot.
Pour the beer into the pot, scraping to deglaze the pan.
Add the meat and vegetables back into the pot. Add broth, rosemary and thyme. Bring to a gentle simmer.
Cover with an oven safe lid, transfer to the oven and cook until fork tender, about 4 hours and up to 8.