How does one find the temperature you should use when baking multiple items such as scalloped potatoes and ham?

Answer 1

Set the oven to an average temperature at which your various dishes will cook effectively and regulate the time they spend in the oven by putting slowest-cooking dishes into the oven first, followed by dishes which cook more quickly, at appropriate time intervals.

This is exactly the same principle used with stovetop cooking; for example, when cooking a casserole or stew, the ingredients will be added at intervals, so onions might be cooked first, followed by spices and dry herbs, followed by meat and hard vegetables (carrots, potatoes, etc), followed by liquid (stock, wine, etc), followed close to the end of cooking by quick-cooking vegetables, fresh herbs and so on.

Another answer:

Ovens were in use long before clocks were invented. For dishes other than breads, cakes and so on, where quantities, times and temperatures might be crucial, oven temperatures and times are simply guidelines. For example, you might cook a roast for 15 minutes per pound at 400F, or 20 minutes per pound at 350F (30 minutes per kilo at 200C, 40 minutes per kilo at 180C) or at other time/temperature ratios to suit whatever else you're cooking in the same oven at the same time.

If the recommended cooking temperatures are different, I would probably go with 350F degrees for everything. Just prepare the scalloped potatoes and ham, put them both in the oven, and cook until they are both done. (A lot depends on whether you are using a pre-cooked ham, or making scalloped potatoes from scratch). If the potatoes are getting too brown on the top, cover them with foil; if they seem to be ready an hour before the ham, take them out of the oven, leave covered and return them about 15 minutes before serving time to reheat. As long as you don't drastically overcook the ham (so it's dried out), everything will turn out fine.

This is true of many other combos -- roast chicken and baked beans, meatloaf and baked potatoes, and so on.

Another answer:

Scalloped potatoes take much longer than less dense vegetable dishes. I pre-cook my scalloped potatoes and take them out 20 - 25 minutes before they are done. Then I put the ham in and 20 - 25 minutes before the ham is done I turn up the heat a little and return the scalloped potatoes to finish in the oven at the same time as the ham.

If in a hurry do your scalloped potatoes in the oven and, meanwhile, cook your ham in the microwave. If you are unsure of the time frame for cooking (your microwave has a book on cooking times) slice the ham on a platter that will fit into your microwave, put plastic wrap over it and cook 5 - 8 mins. Check in 5 minutes to see if hot and steamy, and then decorate with pineapple rings (canned) or fresh chunks of pineapple and candied cherries.

Another answer:

I choose the temperature recommended for the meat and adjust the timing of the other food proportionately. 350F is an average baking temperature for most foods.

With both oven and stovetop cooking, don't attempt to cook dishes which require close and careful attention such as souffle or sponge cake, omelette or French toast, and so on) at the same time you cook less demanding dishes.

...

Think "low and slow". Whatever item has the lower cooking temp, go by that. Adjust your cooking times accordingly. As for scalloped potatoes and ham, I would go at a low temp (around 275) until the ham has an hour or so left and put in the potatoes. After the hour has passed, take the ham out, crank it up to 450 or 475 and flash sear the top of the potatoes. It will take about 15 minutes.

The biggest thing, and the reason why people will say to raise the temp for multiple items is opening the oven. Every time you open it to peer in, you add another ten minutes or so to cooking time. Opening it to, say, put the cover fully off and insert another dish can cost you 250 degrees and 20 minutes of cooking time. Adjust your times accordingly, and keep that door closed!