how long do you cook roast in the oven
3. Heat the oven to 500 degrees for a raw roast, 375 for a pre-browned one. 4. Place the roasting pan in the oven; cook for 10 minutes, then lower the heat to 300 degrees. 5. Cook for about 45 minutes, then start checking the roast's temperature with an instant-read thermometer.Remove the roast when the internal temperature, measured as deep into the roast as you can get, reads 165 degrees.6.. Heat the oven to 500 degrees for a raw roast, 375 for a pre-browned one. 4. Place the roasting pan in the oven; cook for 10 minutes, then lower the heat to 300 degrees. 5. Cook for about 45 minutes, then start checking the roast's temperature with an instant-read thermometer.