Sweet Potatoes Au Gratin
- Prep Time: 30 minutes
- Cook Time: 1 hour
- Total Time: 1 hour 30 minutes
- Yield: 10 1x
- Category: Dinner
Ingredients
Scale
- 3 large sweet potatoes (any color)
Au Gratin Sauce:
- 6 tablespoons unsalted butter
- ½ medium yellow onion (minced)
- ½ teaspoon sea salt (divided)
- 6 cloves garlic (minced)
- â…“ cup all-purpose flour
- ½ teaspoon cracked black pepper
- 1 tablespoon chopped fresh thyme
- 1.5 cups 2% milk
- 1 cup chicken broth
- 1 cup grated parmesan cheese
- 1 cup shredded gruyere cheese
Topping:
- 15 Ritz crackers (crumbled)
- 2 tablespoons fresh thyme
Instructions
- Preheat the oven to 400°F and grease a 9×13-inch casserole dish.
- Use a mandolin to slice the sweet potatoes into uniform rounds. Aim for a thickness of 1.3mm or 2mm. Set aside.
- In a large skillet over medium-high heat, melt butter. Add minced onion and ¼ teaspoon salt. Sauté for 3-4 minutes, then add minced garlic and sauté until fragrant, about 1 minute.
- Add flour, pepper, and fresh thyme to the skillet, stirring until it forms a paste. Cook for at least 1 minute.
- Reduce heat to medium and slowly whisk in milk, ensuring it doesn’t burn. Once added, the mixture should thicken quickly.
- Slowly add chicken broth, whisking constantly to combine and thicken.
- Remove from heat and gradually add parmesan and gruyere cheese, whisking until melted and smooth.
- Spread 1 cup of cheese sauce evenly on the bottom of the casserole dish. Arrange sweet potato rounds, skin side up, filling the dish.
- Pour remaining sauce over the potatoes, pushing it down between the slices.
- Sprinkle Ritz cracker crumbs over the top, covering the dish.
- Bake covered for 30 minutes, then uncovered for 30 minutes.
- Let rest for 10 minutes before serving, garnishing with fresh thyme.
Notes
- Gluten-free bread crumbs can substitute for Ritz crackers.
- Uncover the dish for the second half of baking to allow the sauce to thicken.
