Cook the bow tie pasta according to package instructions until al dente. Drain and set aside.
Heat olive oil in a large skillet over medium-high heat.
Add diced onion and cook for 3-4 minutes until softened.
Add minced garlic and cook for 1 minute until fragrant.
Add ground beef to the skillet and cook, breaking it apart with a spatula, until browned and cooked through, about 6-8 minutes. Drain excess fat if necessary.
Sprinkle ranch seasoning mix over the cooked beef and stir to combine.
Pour in beef broth and whole milk, stirring to incorporate the seasoning and beef.
Bring the mixture to a simmer and cook for 3-4 minutes to slightly thicken the sauce.
Reduce heat to low and stir in shredded cheddar cheese until melted and smooth.
Add cooked bow tie pasta and sour cream to the skillet, stirring until the pasta is evenly coated and the sauce is creamy.
Season with salt and black pepper to taste.
Remove from heat and sprinkle chopped fresh parsley over the top before serving.