Ingredients
2 garlic cloves, minced
1 Tbsp melted butter
3 Yukon gold potatoes (about 1½ lb total)
2 smaller parsnips (about 12 oz total)
salt and pepper to taste
1 tsp fresh thyme leaves
6 oz (about ¾ cup) crème fraiche, divided
1 cup chicken broth
2 oz Parmigiano-Reggiano, finely grated
cayenne to taste
Directions
Preheat oven to 375°
Peel potatoes and parsnips then transfer to a bowl of water until needed. Prepare baking dish by adding garlic and melted butter, brushing bottom and sides to thoroughly coat.
Thinly slice 1 potato with a mandolin and evenly layer on bottom of baking dish. Season with salt and pepper, then a very light dusting of thyme leaves and ⅓ of the Parmigiano-Reggiano. Drizzle in ⅓ of the crème fraiche. Thinly slice 1 parsnip with vegetable peeler and evenly layer into the baking dish. Lightly season with salt.
Repeat every step in the previous paragraph to create second layer in this gratin.
Layer top of dish with the last thinly sliced potato, lightly seasoned with salt. Pour in chicken broth, it should reach the edge of the last potato layer. Evenly distribute the remaining crème fraiche, lightly dust with cayenne, then the last of the Parmigiano-Reggiano.
Transfer to the center of a preheated oven and bake 45-60 minutes or until top is golden brown and potatoes are knife tender.