How long to bake quiche at 350 degrees when it should be 400 degrees for one hour?

If you need to bake quiche at 350 degrees instead of 400 degrees, it will take longer to cook. Typically, you should increase the baking time by about 15-20 minutes, so aim for a total of 1 hour and 15 to 1 hour and 20 minutes. Keep an eye on it to ensure the filling is set and the crust is golden brown. A knife inserted in the center should come out clean when it's done.