Whisk together vegetable broth, soy sauce, brown sugar, and sesame oil in a small bowl until sugar dissolves completely. Set aside.

Cook lo mein noodles according to package directions until al dente. Drain and set aside.

Heat 1 tablespoon oil in a large skillet over medium-high heat.

Cook carrots for 3-4 minutes, stirring occasionally, until golden-brown. Remove to a plate.

Add another tablespoon of oil and cook onions for 3 minutes until translucent with browned edges. Remove and set aside with carrots.

Add more oil and cook broccoli for 3 minutes until bright green and crisp-tender. Remove to the plate.

Cook bell peppers for 2-3 minutes until slightly charred but still crunchy. Remove to the plate.

Add all cooked vegetables back to the skillet.

Press garlic directly into the pan and toss everything together for 30 seconds until fragrant.

Add cooked noodles and pour sauce over everything.

Using tongs or wooden spoons, toss everything together for 3-5 minutes until noodles and vegetables are coated and sauce thickens slightly.