Creamy Harvest Root Vegetable Bake

2 Yukon Gold potatoes, scrubbed and sliced thin
1 turnip, peeled and sliced thin
1 rutabaga, peeled and sliced thin
1 parsnip, peeled and sliced thin
1 celery root, peeled and sliced thin
2 Tbsp butter
2 garlic cloves, minced
1 1/4 cups chicken broth
1 cup heavy cream
1 Tbsp chopped fresh thyme
1 pinch ground nutmeg
1 pinch cayenne pepper
salt and black pepper to taste
1/4 cup finely grated Parmigiano-Reggiano cheese, divided

Preheat the oven to 375 degrees. Coat a 9x13 inch baking dish with olive oil or cooking spray.
Get out a large pot, fill with water and add salt, and bring water to a boil. Add the vegetables and cook uncovered for 3 minutes (you're just blanching the veggies, not cooking them.)
Prepare large ice bath in sink.
Dump veggies into a large colander or strainer, then immediately immerse the strainer of veggies into the ice bath for several minutes until veggies are cold - this stops the veggies from cooking further after being drained.
Remove the strainer of veggies from ice bath and drain well.
In a large skillet over medium-low heat, add the butter and garlic and cook for about 1 to 2 minutes or until garlic gets fragrant.
Add the broth, heavy cream, thyme, nutmeg, and cayenne pepper, stir and continue cooking until mixture begins to simmer and thicken, about 5 minutes.
Spread vegetables evenly in the prepared baking dish.
Pour creamy mixture from skillet evenly over vegetables and sprinkle half of the grated Parmigiano-Reggiano cheese over the top.
Cover the baking dish with aluminum foil, put dish on top of a baking sheet to catch any spills, and bake in the preheated oven for 40 to 45 minutes.
Pull the rack forward from the oven, uncover the casserole and top with remaining Parmigiano-Reggiano cheese.
Slide oven rack back into the oven and bake uncovered until top and edges of casserole are browned and bubbly hot, about another 30 to 35 minutes.
Remove casserole from oven and allow to rest about 10 minutes before serving.
Serve warm as a side dish or vegetarian main dish.
Will serve about 6 to 8.