In a bowl, whisk together the soy sauce, brown sugar, broth, minced garlic, corn starch and sesame seeds until well combined. Set aside.
Cook the lo Mein noodles according to package instructions. Once cooked drain and add back into the pot and cover to keep warm. Toss with some oil to avoid the noodles from sticking.
Thinly slice the steak into strands and in a bowl season with salt and pepper.
Heat your skillet or wok on medium high heat with 1 Tbsp of oil. Once hot, add the steak and cook for about 4-5 minutes, or until crispy. Remove from pan and cover to keep warm.
Add the shredded carrots and sliced peppers to the pan and cook for 3-4 minutes, or until tender.
Once tender, add 1 Tbsp butter along with the minced garlic, broccoli florets and green onion and cook until broccoli is tender 2-3 minutes. Season veggies with salt and pepper to taste.
Add the cooked steak back into the pan and mix. Pour in the stir fry sauce and cook on medium heat allow the sauce to simmer and thicken, cook for about 2-3 minutes.
Add the cooked noodles in and gently mix until everything is well combined.
Remove from heat and top with more chopped green onion and sesame seeds and serve immediately.