Even without cream, you can easily make this using milk, skim milk powder, and cheese.
Going out just to buy heavy cream is a pain, so I just made this with what I had at home.
You can bake this without bothering to bake the tart crust first, but for the best color and fragrance, put a weight on the pie crust, then pre-bake at 180 degrees Celsius for 20~30 minutes. If you don't beat the egg real well with a whisk, the egg whites will harden like in the picture.
Enjoy Japanese food around the world.