For the potato-squash mixture:
1-1/2 pounds potatoes, peeled if skins are thick, and very thinly sliced (we used a mix of russets and red-skinned potatoes)
1 pound butternut squash, peeled and very thinly sliced
1-1/2 cups chicken broth
1 cup half-and-half
Salt and pepper
For the filling:
1 T butter
1 pound minced alliums (we used a mix of leeks, shallots, and onions)
3 ounces grated sharp Cheddar cheese
2 T minced fresh parsley
1/2 tsp smoked paprika
For the topping:
1/2 cup panko or breadcrumbs (optional - omit for gluten free)
1/3 cup minced walnuts
1/4 cup grated Parmesan cheese
2 T melted butter
1. Preheat the oven to 400 degrees and spray a 9x13 baking dish with oil.
2. Combine all of the potato-squash mixture ingredients in a large soup pot. Bring to a boil, and then simmer 8-12 minutes, until the potatoes are just tender.
3. Meanwhile, melt the butter for the filling in a large skillet. Add the alliums, and cook over medium heat until nicely softened and browned. Sprinkle with salt and pepper to taste.
4. In a separate bowl, toss together the Cheddar, parsley, and paprika.
5. Layer half the potato-squash mixture into the baking dish. Scatter the browned alliums and cheese mixture on top, and then add the remaining potato-squash mixture.
6. Stir together the topping ingredients in a small bowl, and sprinkle over the top of the potatoes.
7. Bake until bubbly and browned, uncovered, 25-30 minutes.
8. Let the dish sit, uncovered, for at least 10 minutes before serving. This allows the liquid to thicken slightly.