Lentil Stuffed Squash with Mushroom Gravy

Name: Lentil Stuffed Squash with Mushroom Gravy
Ingredients: * 4 medium acorn squash; * 1 cup dry green lentil, soaked overnight and rinsed well; * 2 1/2 vegetable broth; * 2 tablespoon coconut oil; * 2 garlic clove, minced (optional); * 1 small onion, finely diced (optional); * 2 carrot, finely diced or grated; * 1 celery stalk, finely diced; * 1 heaping teaspoon dried thyme; * 1/2 heaping teaspoon cumin; * freshly cracked pepper; * sea salt, to taste