Preheat oven to 350°F. Grease 13 x 9-inch baking dish; set aside.
Boil spaghetti in a large pot of salted boiling water, just until barely al dente (about 1 minute less than called for on the box). Drain.
Meanwhile, fry the bacon in a large skillet or Dutch oven over medium-high heat until crisp, about 7-10 minutes. Use a slotted spoon to transfer the bacon to a paper towel lined plate, reserving the drippings in the pan.
Add butter to the skillet with the drippings. When the butter melts, add the onion, celery, bell pepper and mushrooms. Sauté until tender, about 5-7 minutes. Add the garlic and cook for 30 seconds, or until fragrant.
Stir in the cooked spaghetti, cooked bacon, turkey, ½ cup of the Parmesan cheese, cream of mushroom soup, Alfredo sauce, chicken broth, white wine, pepper and frozen peas. Toss gently to combine; transfer to the prepared baking dish.
Sprinkle remaining ¼ cup of Parmesan and slivered almonds on top. Bake, uncovered, for 20-25 minutes, or until the filling is hot and the nuts are lightly toasted.