Bring 2 cups of broth to a gentle simmer in a medium saucepan. Add ramen noodles and cook for 3-4 minutes until tender but not mushy. Drain noodles and set aside in a bowl, keeping the empty saucepan for the next step.

In the same saucepan, melt butter over medium heat. Add softened cream cheese, stirring constantly until completely smooth and no lumps remain - this usually takes about 2 minutes. The mixture should be silky and uniform.

Gradually pour in milk while whisking continuously to prevent any lumping. The mixture should be smooth and creamy before moving to the next step.

Sprinkle in garlic powder, onion powder, black pepper, and salt. Stir well to distribute seasonings evenly throughout the sauce base. Taste and adjust salt as needed.

Slowly add shredded cheddar cheese in small handfuls, stirring constantly until each addition melts completely. Keep heat at medium-low to prevent the cheese from becoming grainy. The sauce should coat the spoon smoothly.

Return cooked noodles to the saucepan and gently toss until every strand is coated in the creamy cheese sauce. Serve immediately while hot, garnished with green onions and red pepper flakes if desired.