I have two frozen sides from the Honey Baked Ham store that I want to cook simultaneously - they are the Au Gratin Potatoes and the Sweet Potato Souffle. The first should cook at 375 Degrees Fahrenheit for 45 minutes, covered, then 13-15 minutes uncovered and sit for 2-3 minutes after removed. The second, should cook at 375 Degrees Fahrenheit for 45 minutes, covered, then 27-30 minutes uncovered and sit for 2-3 minutes. If I want them to be done at the same time and put the Sweet Potatoes in first (since they need to cook longer) the temp will obviously drop when I add the frozen Au Gratin Potatoes.... any help would be greatly appreciated!
The second item needs to be in the oven for 15 minutes more than the first item. Just put that item in the oven, then put the second item in 15 minutes later. Follow all other procedures as indicated in the instructions. The required cooking temperature is the same for both. I am assuming that cooking from frozen is built into the instructions, so that will not really matter for your question. The temperature will drop a bit when you open the oven door, but your oven will catch up in a reasonable amount of time and will not impact the final cooking. Just make sure there is a bit of space between your products when they are both in the oven.