Preheat oven to 350 degrees.
Make Lemon Garlic Sauce: Mix mayonnaise, garlic, lemon juice, and a pinch of salt. Refrigerate while making the squash and stuffing.
Cook the rice as directed on the package, substituting the water for chicken broth. If you use the same rice as I do ( Trader Joe's Wild Rice Medley ), that will be 35 minutes.
Cut the acorn squash in half from stem to bottom, and remove all seeds and weird stringy stuff inside. Pierce the flesh with a fork four or five times for each half of squash.
Cook the squash, cut sides down, on a foil-lined or greased baking sheet for 20 minutes.
Remove the pork from its casing, and put in a medium sized pan with the olive oil over medium heat, breaking into crumbles as it cooks.
When the sausage has started to brown ( but is not necessarily completely cooked through ), add the chopped mushrooms and pecans, and cook over medium heat, stirring occasionally, until both the mushrooms and the sausage are cooked. Turn off the heat.
Add the cooked rice and fresh herbs to the pan with the mushrooms, nuts, and sausage, and stir to combine. Season with salt and pepper, to taste.
Fill each half of acorn squash with a mound of the rice mixture, and place on a baking sheet.
Bake at 350 for 20 minutes.
Remove from the oven, and drizzle with the Lemon Garlic Sauce.