Step 1

To make sauce, heat oil in large saucepan over medium-high heat. Add onion and carrots and cook, stirring frequently, until softened, 5–6 minutes. Stir in garlic and 1 tablespoon sage; cook, stirring frequently, until fragrant, about 1 minute. Stir in turkey, breaking it up with wooden spoon. Add tomato paste and cook, stirring often, until turkey is no longer pink, about 5 minutes. Add wine and simmer until almost evaporated, 1–2 minutes. Stir in tomatoes, 3 tablespoons water, 3/4 teaspoon salt, and 1/4 teaspoon pepper. Reduce heat and simmer, covered, until vegetables are very tender, about 15 minutes, adding more water if needed.

Step 2

Meanwhile, preheat oven to 400°F.

Step 3

Stir together ricotta, egg, 1 1/2 teaspoons sage, remaining pinch salt, and remaining 1/8 teaspoon pepper in small bowl; set aside. Using mandoline, V-slicer, or very sharp knife, cut potatoes into very thin lengthwise slices (about 1/10-inch thick). Put spinach in large bowl and cover with boiling water. Let stand 1 minute; drain and let cool. Squeeze dry and roughly chop.

Step 4

Spread thin layer of sauce over bottom of 9-inch square (2-quart) baking dish. Cover with one third of potato slices, overlapping slightly. Spread half of remaining sauce over potatoes. Cover with another third of potato slices and top with spinach. Spoon ricotta mixture on top and spread evenly. Top with remaining potato slices, remaining sauce, and mozzarella. Cover loosely with sheet of nonstick foil.

Step 5

Place lasagna on baking sheet; bake until potatoes in center of lasagna are very tender when pierced with tip of paring knife, about 1 hour. Remove foil and bake until cheese is lightly browned, about 10 minutes. Let stand 10 minutes and cut into 8 portions.

Step 6

Serving size: 1/8 of casserole