If my plea for you to use crème fraiche goes unheeded, yes,
heavy cream will work here, but the subtle tang and nuttiness you get from the
fermented cream takes this to places the regular stuff just can’t. It also
seems to add some extra smoothness to the texture, and make no mistake; the
mouthfeel with this classic is just as critical as the flavor.
I’ve not tested my theory, but other substitutions like
buttermilk and sour cream should also work similarly. If you don’t have Grand
Marnier, just using vanilla is fine, but the vague scent of orange rind that it
provides the custard is really nice.
You also have the freedom to change the size and shape of
your ramekins. Whether you use fewer, larger ones, or a larger number of
smaller-sized ramekins, the procedure will work exactly the same. Of course,
you’ll have to adjust the cooking times, but the “just set” doneness test will be
your ultimate guide. I hope you give these classic treats a try soon. Enjoy!