We are all lactose intolerant in my family. What might this be like without cream? Would lactaid milk work?

I think TLD might be onto something here. If you try the tofu please let me know how you like it. Be sure you really do reduce the vinegar down to a syrup of just a few tablespoons before adding the tofu.

I think finding a sub for the butter and cream in the recipe will be a challenge. The sauce is butter fat and vinegar rich. Subs that I would typically use for cream-like coconut oil and coconut milk will likely not work here because of the traditional french flavors and the red wine vinegar. Lactaid may work, but it probably doesn't have the fat content of heavy cream to enrich the sauce.