Mostly, I just try to do less baking in the summer. When I do have to bake, I try to do it in the evenings when it's cooler, and as much as possible do several things at once so the oven doesn't have to heat all the way up multiple times. E.g. if I need bread for the week, muffins for breakfast, and cookies for a friend, I'll try to do them all in the same day and time the prep so one comes out as the next goes in. As much as possible, I cook on the stovetop instead (e.g. saute veggies instead of roasting), and use crockpots, rice cookers, instapots, etc as much as possible as they produce less heat. I also tend to turn the AC off while I'm cooking, and just suffer through it until I'm done, but we don't have central air, only wall units.