Step 1

Preheat oven to 425°F.

Step 2

Brush 1 tablespoon oil on cut side of squash halves; season with ½ teaspoon salt and ¼ teaspoon pepper. Place squash, cut side down, on a parchment-lined baking sheet; bake until slightly tender, 20 to 25 minutes. Remove from oven; turn cut side up.

Step 3

Meanwhile, heat 1 tablespoon oil in a large skillet over medium-high. Add mushrooms and shallot; cook, stirring occasionally, until tender, about 5 minutes. Add spinach; cook until wilted, about 1 minute. Season with ¼ teaspoon salt and ⅛ teaspoon pepper. Remove from heat and fold in bread and cheese.

Step 4

Divide mushroom mixture among squash halves, return to oven, and bake until tender, 8 to 10 minutes. Increase temperature to high broil. Broil until lightly browned, 3 to 5 minutes.

Step 5

Toss greens with lemon juice and remaining 1 tablespoon oil, ¼ teaspoon salt, and ⅛ teaspoon pepper. Serve salad with squash.