This one’s a keeper for sure. It takes some time but it is worth it. Here are all of the great fall root veggies in one place, topped with cheese and cream., What could be better? This was another installment of making new receipts for the holidays and this one comes from Alexa Weibel in NYTimes Cooking and didn’t disappoint. This is a root vegetable gratin that really delivers on taste and customer satisfaction.
In order to fill a 9′ x 13″ pan, you’ll need: FOR THE CREAM: 3-4 cups half & half, 3 Tbs unsalted butter, x2 large chopped shallots, 1 Tbsp whole black peppercorns, 6 cloves garlic (finely chopped), 6 bay leaves (whole), 3 thyme sprigs (fresh), 1/2 tsp grated nutmeg, 2 egg yolks, salt and pepper. FOR THE VEGGIES: 2-3 Large red/russet potatoes (not peeled), 3-4 large red beets (peeled), 1 large or 2 medium sweet potatoes (peeled), 1/2 large or 1 small butternut squash “necks” (peeled), 10-16 oz gruyere cheese (grated), fresh thyme, salt and pepper.
Preheat oven to 375.
First, make the cream. Melt the butter in a large saucepan over medium heat and add in the shallots, garlic and black peppercorns. Cook until shallot has softened – about 5 mins. Add in the half & half (use 3 or 4 cups depending on how creamy you’d like it to be, in the end you don’t have to use it all), bay leaves, thyme, nutmeg and some salt and bring to a gentle boil. Reduce the heat and allow to simmer for about 20 minutes, whisking occasionally, until slightly reduced and thickened.
Strain the cream mixture through a fine sieve into a large bowl, and then return the now strained mixture back into the saucepan. In the large bowl, whisk the egg yolks together and then add in about 2-3 Tbsps of the still warm cream, one Tbsp at a time, into the egg yolks in order temper them (and avoid scrambling the egg yolks). Whisk the tempered egg yolks into the warm cream.
Cut the red potatoes into thin slices (1/8″) using a sharp knife or a mandolin. Place the potato slices into the warm cream in the saucepan to start their cooking process.
Grease a 9′ x 13″ high sided pan with some unsalted butter making sure you get into the corners and edges.
Cut peeled beets into thin slices (again, 1/8″) and spread them, slightly overlapping, into a single layer across the bottom of the greased pan. Season this layer with a little salt and pepper and add enough grated cheese to mostly cover the layer.
Cut the peeled sweet potatoes into thin slices and repeat the process above but this time creating x2 layers, seasoning between layers, and then drizzling just a little bit of the cream and some fresh thyme leaves across the layers after adding the grated cheese.
Cut the butternut squash “neck” in half lengthwise and then cut them into thin half moon slices. Add a layer or two of the thinly sliced, peeled butternut squash, season with S&P, and add grated cheese across the top.
For the final layer(s) add the potato slices from the cream sauce to create a creamy potato layer that covers the top. Season and then add the remaining grated cheese and some fresh thyme leaves.
Place the pan, uncovered, into the preheated over and cook until a fork easily pushed through all of the layers – about 1 hour.
Remove from oven, let stand for 10-15 mins before serving.