Boil ramen noodles for 2–3 minutes, no seasoning packet, just clean, pure noodles. Drain them, but keep a splash of starchy water aside. That’s your secret to sauce that sticks.
In a skillet, melt butter over medium heat. Add garlic and red pepper flakes. Stir until the garlic softens and fills the air with that familiar, comforting aroma about 30 seconds.
Pour in soy sauce and sprinkle in brown sugar. The mix will bubble and turn syrupy in seconds. That’s your cue to add the noodles.
Use tongs to swirl the noodles through the glossy sauce until every strand shines. If it thickens too quickly, loosen with a bit of the saved water.
Push noodles to one side, crack the egg in, and stir quickly. The egg cooks into a silky, golden coating like a light blanket of flavor.
Turn off the heat. Add a squeeze of lime, toss again, and top with sesame seeds and green onions.