This recipe would work well in the winter, but in the first cold days of June in Montreal, it was equally welcome! It calls for half-and-half, so I used half lactose-free milk and half lactose-free cream (you could consider using coconut milk instead of the cream). My mother sliced the potatoes by hand to help me out, though you could use a mandolin if you’re more comfortable with that. I served it with blueberry and green tea duck sausages and cranberry maple sausages (they were both good, but the latter my favorite; the Engineer preferred the former).
1 Tbsp. chopped fresh sage
1 Tbsp. chopped fresh thyme
2 lbs. russet potatoes, peeled, sliced 1/8” thick
2 lbs. sweet potatoes, peeled, sliced 1/8” thick
1 ½ tsp. salt
½ tsp. pepper
¾ cup lactose-free milk
¾ cup lactose-free cream
½ cup low-sodium chicken broth (or vegetable broth if you wish)
1 ½ cups grated lactose-free gruyere
Preheat oven to 425 °F. Line a large, rimmed baking sheet with foil. Grease a 3-quart shallow baking dish.
Combine the sage and thyme in a small bowl.
In the baking dish, layer 1/3 of the potatoes and 1/3 of the sweet potatoes, alternating the slices. Sprinkle with 1/3 of the herb mixture and 1/3 each of the salt and pepper. Repeat layering to use up all the ingredients.
Combine milk, cream and broth and pour over the potatoes. Place dish on the baking sheet and cover with foil. Bake for 50 minutes. Uncover, sprinkle with cheese and bake until golden and bubbling, 20 to 25 minutes longer. Let rest for 10 minutes before serving.