From: Chef John Andres, BOS Restaurant, Des Moines, IA. Yield: 16 servings.
1 Tbsp. butter
6 cloves minced garlic
2 minced shallots
1½ Tbsp. kosher salt
½ tsp. ground white pepper
1 tsp. cinnamon
½ tsp. nutmeg
¼ tsp. cayenne pepper
2 cups soymilk, plain
4 sprigs fresh thyme
2 bay leaves
3 egg yolks
3 lb. butternut squash, peeled and sliced 1/16" thick
6 Idaho potatoes, peeled and sliced 1/16" thick
2 Tbsp. butter, cold (for buttering the pan)
to taste, salt and pepper
2 cups shredded Parmesan cheese, divided
Over medium heat in a large saucepan, add butter; melt. Add garlic and shallots, and stir until translucent. Add seasonings; mix to a paste consistency. Whisk in soymilk, add thyme and bay leaf and bring to a simmer. Remove from heat; cool for 10 minutes. Remove bay leaves and thyme. In a separate medium mixing bowl, add egg yolks and whisk. Slowly add soymilk mixture, whisking constantly. Using a mandolin, very thinly slice squash and potatoes. In a well-buttered pan, place a single slightly overlapping layer of potatoes. Sprinkle very lightly with salt, pepper and Parmesan cheese. Next, place a single slightly overlapping layer of squash into the pan, arranging squash perpendicular to the direction that the potatoes were laid. Sprinkle lightly with salt, pepper and Parmesan cheese. Continue sprinkling each layer with salt, pepper and cheese. Continue alternating layers of potatoes and squash, alternating directions with each layer.
Once all the squash and potatoes have been used (or you are within the top ¼” of the pan), slowly pour cream mixture over squash and potatoes. You may have to top the pan from side to side, or carefully press down the top of the vegetables to allow mixture to flow down among the layers. Cover pan with aluminum foil and bake for 60 minutes at 375°F. Remove pan from the oven, uncover, and allow to cool slightly. Place the pan into a larger high-sided pan to catch any possible overflow. Lightly drape a sheet of parchment paper over pan. Using another 11" square pan, press down firmly atop potato and squash to compress layers. (Some liquid may flow around sides of the pan.) Place a heavy weight atop the second pan (a few large food cans work great) and refrigerate overnight. Remove weights and pan from the mixture, then gently peel away parchment paper. With paper towels, wipe away excess moisture from sides of pan. Cover with foil and bake at 375°F until warmed throughout, about 45 minutes. Uncover and sprinkle top layer with ½ cup Parmesan cheese. Bake uncovered until browned. Cut and serve immediately.
Photo: The Soyfoods Council