In a large pot, bring salted water to a boil. Cook 8 ounces of spaghetti until al dente, about 8-10 minutes. Drain the spaghetti, reserving ½ cup of pasta water.
In a skillet, heat over medium heat and add 4 slices of chopped bacon. Cook for 5-7 minutes until crispy. Transfer to a paper towel-lined plate.
In the same skillet, reduce heat to low and add 2 tablespoons of unsalted butter. Once melted, add 2 cloves of minced garlic and sauté for 1 minute.
Pour 1 cup of heavy cream into the skillet, increase heat to medium, and simmer gently. Stir continuously, then add 1 cup of grated Parmesan cheese, whisking until smooth.
Add the drained spaghetti and crispy bacon to the sauce, tossing to coat. Use reserved pasta water if needed to adjust consistency.
Remove from heat, transfer to plates, and garnish with chopped parsley. Serve immediately.
Notes
Store leftovers in an airtight container in the fridge for up to 3 days. Reheat gently with a splash of milk or cream to restore creaminess.