How long to cook 4 crustless quiches at the same time?

When cooking four crustless quiches at the same time, it typically takes about 35 to 45 minutes at 350°F (175°C). Ensure they are placed on the same rack with enough space for air circulation, and check for doneness by inserting a knife or toothpick in the center; it should come out clean. You may need to add a few extra minutes if they are not fully set. Always keep an eye on them towards the end of the cooking time.