My guess would be you have no idea if you were born in the US, what quark is. Sounds like a duck call. But it is actually a light creamy cheese that is similar to Greek yogurt or sour cream. It has way less calories and is higher in protein. It is great for baking. And it makes the Kasekuchen a German cheesecake.
The celebrated patissier Coquelin bought La Patisserie Bourdaloue (which is still up and baking on the rue Bourdaloue) in 1909, and created, among other things, this famous pear tart with frangipane / almond cream. Certain desserts stand the test of time and one of those classics is la tart bourdaloue. It has remained one of my favorites, both to make and to eat.