Butternut Squash au Gratin with Wild Mushrooms and Crispy Bacon

Ingredients

• 0.3 cup beef stock unsalted (such as Swanson)
• 0.3 teaspoon pepper black freshly ground
• 4 pounds butternut squash diced divided peeled finely
• 4 ounces chanterelles sliced
• 1.5 tablespoons sage fresh chopped
• 2  spring onion thinly sliced
• 0.5 teaspoon kosher salt divided
• 1 tablespoon olive oil extra virgin extra-virgin
• 6 ounces oyster mushrooms sliced
• 0.5 cup parmesan divided grated
• 2 tablespoons part-skim ricotta 
• 4 ounces mushroom caps sliced
• 2 slices bacon 

Equipment

• bowl
• frying pan
• oven
• baking pan
• potato masher
• aluminum foil
• broiler

Directions

1. Preheat oven to 35
2. Heat a large skillet over medium-high heat.
3. Add oil; swirl to coat.
4. Add green onions; saut 30 seconds.
5. Add 6 cups squash; saut 2 minutes. Reduce heat to medium-low, and stir in 1/4 teaspoon salt. Cook, covered, 15 minutes or until tender. Increase heat to medium-high. Cook, uncovered, 2 minutes or until liquid evaporates, stirring frequently.
6. Place squash mixture in a large bowl; mash with a potato masher or fork until smooth.
7. Cook bacon in a large nonstick skillet over medium-high heat until crisp.
8. Remove bacon from pan, reserving drippings in pan; crumble bacon.
9. Add chanterelles, shiitakes, and sage to drippings; saut 8 minutes or until mushrooms are browned.
10. Add stock; cook 3 minutes or until liquid almost evaporates.
11. Add mushroom mixture, remaining 2 cups diced squash, remaining 1/4 teaspoon salt, 1 ounce Parmigiano-Reggiano cheese, ricotta cheese, and black pepper to mashed squash mixture, stirring to combine. Spoon squash mixture into a broiler-safe 11 x 7-inch glass or ceramic baking dish coated with cooking spray. Cover with foil; bake at 350 for 1 hour.
12. Remove pan from oven; discard foil.
13. Preheat broiler to high.
14. Combine bacon, remaining 1 ounce Parmigiano-Reggiano, and oyster mushrooms in a bowl; sprinkle over gratin. Broil 6 minutes or until lightly browned.
15. Let stand 5 minutes before serving.