4 poached apples
4 small celery roots, peeled
6 tablespoons cold butter, cut into tiny pieces
Salt and pepper
2 cups crushed gingersnaps
Additional butter for greasing the pans
Reserved glaze from apple poaching
Preheat the oven to 275°F. Butter the inside of 4 individual gratin casserole dishes or 1 ten-inch baking dish with a pastry brush.
Cut the ends off the apples, cut into quarters and remove core. Slice crosswise into ¼ inch slices with a sharp knife.
Slice celery root into ⅛ inch slices using a mandolin. If you don’t have a mandolin, a knife will work. Be careful not to slice thicker than ⅛ inch or the pieces will take longer to cook.
Crush gingersnaps by placing in a plastic bag and rolling over with a rolling pin.
Place slices of the poached apple to cover the bottom of the dish and spread out the pieces fanned out (it does not need to be in a tight fan). Follow with a layer of celery root slices, shingling and layering in the same way. Repeat twice. After the third layer of each, season lightly with salt and pepper, dot with butter, sprinkle with gingersnap crumbs and drizzle with a tiny bit of apple glaze.
Continue layering, seasoning and adding butter and gingersnap crumbs after every third layer of the apple and celery root. The layers should come up slightly higher than the top of the dish.
Finish with salt and pepper, butter and gingersnap crumbs.
Cover the top with a lid, or tinfoil if you do not have a lid, and place on a baking sheet.
Bake in the oven approximately 30 to 45 minutes or until the apple and celery root has cooked down to ½ an inch below the top of the dish and a golden brown crust has formed. Test for doneness using a cake tester to probe for a lack of resistance from the celery root.
Let cool for at least 5 minutes before tasting.
Glaze with reduced apple poaching liquid immediately before serving.