Butternut Squash and Potatoes Au Gratin

Butternut Squash and Potatoes Au Gratin

Yield 12 Servings

Free of: gluten and top 8 allergens.

Ordinary ingredients become extraordinary when combined in this casserole!



4 tbsp dairy-free, soy-free margarine, such as Earth Balance buttery sticks

2 cups leeks, washed well and thinly sliced, white and pale green parts only

3/4 tsp sea salt, divided (1/4 tsp + 1/2 tsp)

2 tsp minced garlic

1/3 cup garbanzo bean flour

4 cups unsweetened rice milk

1 bay leaf

1 tsp chopped fresh thyme

1/8 tsp white pepper

1/8 tsp ground nutmeg

2 pounds russet potatoes, peeled and sliced 1/8-inch thick (see recipe notes)

1 pound butternut squash, peeled, seeded, quartered and sliced 1/8-inch thick (see recipe notes)

2-1/2 cups cheddar-style shreds, such as Daiya, divided (2 cups + 1/2 cup)

1/4 cup gluten-free breadcrumbs or panko, optional

1/2 tsp smoked paprika, optional


  1. For cream sauce, in a medium saucepan, melt margarine over medium heat. Add the leeks and 1/4 teaspoon salt and cook for about 8 minutes until very soft, stirring occasionally. Add garlic and cook for another 30 seconds.
  2. Add flour and cook for 1 minute, stirring constantly. Gradually whisk in milk. Add bay leaf and thyme and increase heat to medium-high. When sauce comes to a simmer, lower heat to medium-low and gently simmer for 15 minutes, stirring occasionally. Remove from heat. Whisk in remaining 1/2 teaspoon salt, pepper, and nutmeg. Remove and discard bay leaf. Set sauce aside.
  3. Preheat oven to 400° F.
  4. To assemble, in a large bowl, add potatoes, squash, reserved cream sauce, and 2 cups cheddar-style shreds. Gently toss well to combine. Transfer to a lightly greased 13x9-inch baking dish. With fingers separate and arrange butternut squash and potatoes so they are mixed fairly evenly. Cover tightly with foil sprayed with cooking spray. Bake for 45 minutes.
  5. While casserole is baking, in a small bowl, mix the remaining 1/2 cup cheddar shreds, bread crumbs, and smoked paprika.
  6. Remove foil and sprinkle bread crumb mixture over the casserole. If you choose to omit the crumb topping, sprinkle with remaining half cup of cheddar-style shreds, omitting the breadcrumbs and paprika. Continue to bake, uncovered until vegetables are tender, about 25-30 additional minutes. 
  7. Let rest for 15 minutes before serving.


  • Make the sauce before slicing the potatoes and squash. This way you will not have to place the potatoes in water which will release the starches needed for a creamy casserole.
  • Cut the butternut squash and potatoes into 1/8-inch slices for even cooking. We highly suggest using a mandolin for slicing. It is possible to cut by hand, but the slices may be uneven and the task will take so much longer.
  • To prep squash like a pro, lay the squash on its side. Using a large, sharp chef's knife, trim the top and bottom, then cut crosswise through the middle. Peel the skin. Stand each section on its flat side and cut in half lengthwise. Using a melon baller or a large spoon, scrape out the seeds and any pulp or stringy bits. Place each half cut side down and slice lengthwise in half again. Cut 1-pound of the squash into 1/8-inch slices.
  • We have slightly modified this recipe that we first developed for Allergic Living Magazine.

Courses Veggies & Sides

Recipe by Allergy Chefs at