In a large skillet or wok, melt the butter over medium-high heat. Add the minced garlic and ginger, and sauté for 1-2 minutes until fragrant.
Add the cooked noodles to the skillet. Pour in the soy sauce, teriyaki sauce, and brown sugar. Toss the noodles to coat them evenly, and season with salt and pepper.
Remove the skillet from heat. Drizzle with sesame oil and, if desired, garnish with chopped scallions and sesame seeds. Serve immediately.