Bring a large pot of salted water to a boil and cook the rotini pasta according to package directions until al dente.

While pasta cooks, heat olive oil in a large skillet over medium-high heat and sauté the diced onion until translucent.

Add the ground beef to the skillet and cook until fully browned, breaking it into small crumbles with a spatula; drain excess grease.

Stir in the taco seasoning and the undrained Ro-Tel tomatoes into the meat mixture.

Reduce heat to medium-low and add the cubed cream cheese and milk, stirring continuously until the cheese is completely melted and the sauce is smooth.

Drain the cooked pasta and incorporate it into the skillet, tossing to coat evenly with the sauce.

Sprinkle with shredded cheddar cheese and stir until melted and well combined.

Serve immediately, garnished with optional cilantro or jalapeños.