Tough meat cuts such as bottom round roast are best when braised to provide moist heat and help the meat retain moisture. Braised beef roasts are generically referred to as pot roasts.
You might start by searing the meat in a bit of oil to brown the outsides, working in a cast iron skillet or an oven-safe pan such as a Dutch oven.
After searing the meat, add enough beef broth, and/or wine to cover at least one-third of the roast and transfer it to the oven, in a covered oven pot.
Spoon the liquid over the roast periodically as it cooks to keep the meat moist throughout.
Temperature and Time
Bottom round roast should be cooked at a maximum of 300 degrees Fahrenheit or lower to allow the collagen and connective tissues in the meat to break down.
The length of time really depends on the size of the roast and the actual temperature; the time increases as the temperature decreases.
A typical bottom round roast that weighs 3 to 4 pounds should be slow roasted for about 4 hours to cook to well-done with an internal temperature of 180 to 190 F.
You can even make the roast in a slow cooker, which takes roughly 7 hours on the low heat setting.
While you might typically eat beef at medium-rare or medium doneness, this doesn't allow enough time to break down the collagen, connective tissue and tough meat fibers.
Don't forget to slice the beef against the grain.