Preheat the oven to 400 degrees F (200 degrees C). Line a baking sheet with parchment paper; place squash on top, cut-side down.

Bake in the preheated oven until skin is easily pierced with a fork, about 45 minutes.

While squash is cooking, fry bacon in a large skillet over medium-high heat until crisp, 5 to 10 minutes. Transfer to a paper towel-lined plate, reserving grease in skillet. Crumble bacon when cool enough to handle.

Cool baked squash until easily handled. Scrape flesh into noodles using a fork. Place noodles and garlic in the skillet with the reserved bacon grease. Cook over medium heat for 2 minutes; reduce heat to low.

Whisk eggs and Parmesan cheese together in a small bowl; add to skillet and stir continuously for 3 minutes. Remove from heat and stir in cooked bacon pieces, parsley, salt, and pepper. Serve immediately.