- 3 lbs (1.5 kg) sweet potatoes
- 2 tbsp (25 mL) olive oil
- 1 tsp (5 mL) salt
- 8 lasagna noodles
- 3 Tbsp (50 mL) vegetable oil or butter
- 1/4 cup (50 mL) all-purpose flour
- 4 cups (1 L) 1% milk, hot
- 1 tsp (5 mL) salt or to taste
- 1/4 tsp (1 mL) pepper
- generous pinch nutmeg
- pinch cayenne
- 2 cups (500 mL) grated mild cheese (e.g. Lappi or mozzarella)
- 1/4 cup (50 mL) grated Parmigiano Reggiano
1. Peel sweet potatoes, cut into 1/4-in. (5-mm) slices, toss with olive oil and salt and place in a single layer on a parchment-lined baking sheet. Roast in a preheated 400°F (200°C) oven until lightly browned, about 30 minutes.
2. Meanwhile bring a pot of water to a boil. Add 1 tbsp (15 mL) salt. Cook noodles 3 to 5 minutes, until just tender. Rinse in cold water and arrange in a single layer on wet tea towels.
3. Melt butter in a large saucepan, whisking in flour. Cook gently, without browning, about 2 to 3 minutes. Whisk in hot milk and bring to a boil, stirring until mixture thickens. Season with salt, pepper, nutmeg, cayenne to taste.
4. To assemble, spoon about 1/2 cup (125 mL) sauce over the bottom of an oiled 9- x 9-in. (2L) baking dish. Line with a layer of noodles, then a layer of roasted sweet potatoes. Spread with 1 1/2 cups (375 mL) sauce and half the grated mild cheese. Repeat layers. Sprinkle with Parmigiano Reggiano.
5. Bake in a preheated 350°F (180°C) oven for 25 to 30 minutes, until bubbling and browned on top. Let rest 10 minutes before serving. Makes 8 to 10 servings.