Preheat oven to 400°F, lightly oil a large baking dish and set aside
Place acorn squash halves cut side up in the baking dish, brush the cut edges with one tablespoon olive oil
Season with salt and black pepper, to taste
Place baking dish in pre-heated oven and roast until the squash is fork tender, about 40 minutes
While the squash is roasting, heat the remaining olive oil in a large skillet at medium heat
Add minced garlic, sauté until golden, 1-2 minutes
Add chopped mushrooms, cook, stirring once or twice, until they soften and brown slightly, about 4-5 minutes
Add onions, continue cooking, stirring occasionally, for another 3-4 minutes
Add green lentils, sage, and wine or broth into the pan, stir occasionally and cook until the mixture thickens slightly, about 8-10 minutes
Remove from heat, add dates and walnuts
Season to taste with salt and pepper
When squash and mixture are both ready slightly fill each half of the acorn squash with the mixture
Sprinkle with cheese if using
Return to the oven and cook another 5-7 minutes to warm fully
Remove from the oven and serve
Enjoy!