Joan--galettes are wonderful, and with no top crust, they are calorie saving! I had perfected a part-buckwheat one the summer that I had to cut most butter from my diet. These days, I use my regular oil-buttermilk pie crust but put it into a ceramic quiche dish and par-bake it before adding the filling.
Whatever crust you use, apples need to be partly cooked before being added. When one of my husband's cousins experimented with a galette for leftover apples at a family reunion, the apples stayed hard. She now cooks them slightly, and they are cooked properly. I have not tried it, but it could be that if the apples are sliced thinly enough, they will bake in a galette without pre-cooking them.