Bring a large pot of salted water to a rapid boil. Add bowtie pasta and cook according to package instructions (8-10 minutes). Reserve ½ cup pasta water before draining.

In a large skillet, melt 1 tablespoon of butter over medium-high heat. Add ground beef, breaking it up with a spatula. Season with 1 tablespoon Cajun seasoning, salt, pepper, and optional red pepper flakes. Cook until browned and crispy (5-7 minutes). Remove beef from skillet.

Lower the heat to medium, add remaining tablespoon of butter, and sauté minced garlic for 30 seconds until fragrant.

Stir in softened cream cheese and allow it to melt. Gradually whisk in milk or half-and-half until smooth.

Mix in grated Parmesan cheese and remaining Cajun seasoning; simmer gently for 2-3 minutes until sauce thickens. Taste and adjust seasoning if necessary.

Return sautéed beef to skillet and add drained pasta, tossing until everything is well-coated. Add reserved pasta water as needed for desired consistency.

Plate hot, adding extra grated Parmesan on top. Garnish with chopped parsley or red pepper flakes if desired.