Food can be baked, braised, or roasted in an oven. Fixing food in the oven can be simple if you know a few tricks.
If a recipe calls for you to bake something at a higher temperature than your pan recommends, simply adjust the temperature down and increase the baking time accordingly. Assuming that meat was room temperature when it went into the oven, the general rule of thumb is to add 2 minutes of cooking time per pound for each 25 degrees you lower the temperature. The colder the food is when it goes into the oven, the longer it'll take it to bake.
Also consider that a roast placed on a rack in a roasting pan will bake (roast) faster than one set directly in a pan because the rack allows more hot air from the oven to circulate around the meat. Then there's the matter of whether or not the temperature inside your oven is the same as the temperature you set it for when you turned it on. Not taking such variables into consideration can result in exceeding the desired internal temperature of the meat, or a roast that's more well done than you like.
Help ensure that you roast your meat to the desired doneness by using a thermometer with a probe that goes into the food in the oven and is attached to a programmable unit that sits outside the oven. A thermometer's display unit should show the current internal temperature, and it should be equipped with an alarm that goes off when the meat reaches the correct internal temperature.
There are other factors that can affect roasting time, such as the size and shape of the meat, the amount of fat and bone, and whether the meat was aged. The best way to ensure that meat is roasted to your liking is to use the suggested roasting time given in a recipe as a gauge to time when you can have your meal ready to serve, and set a programmable thermometer so you'll know when it's actually ready:
130 °F to 140 °F for medium rare
145 °F to 150 °F for medium
155 °F to 165 °F for well done
Casseroles are easier to bake because they're more forgiving: There's seldom any risk that you'll overbake them. But casseroles are everyday fare. Special occasions call for a small extra effort to make special entrées, like the Standing Rib Roast.
The most important thing to keep in mind when you prepare foods in the oven is that each time you open the oven, it will take it some time to recover lost heat. An electric oven will take longer to recover than will a gas oven. Adding a pizza stone can help any oven retain heat when the oven door is open, or at least recover the heat you lose more quickly. A more expensive but more efficient option is to add a Hearth Kitchen Hearthkit Brick Oven Insert.