Heat up your wok or pan over medium -high heat. Add the oil and let is start to smoke. Add in the garlic, ginger, red pepper flakes, and chili pepper if using. Sauté for a couple of minutes until fragrant.
Then add in the bag of frozen vegetables. Stir and let cook about 5 minutes until the vegetables are warmed throughout.
Add in the shrimp and sauté a few minutes longer. Once mostly cooked and pink, add in the soy sauce and brown sugar. Give everything a stir and let simmer for a few minutes.
Then add in your cooked vermicelli noodles, continue to stir until everything is completely combined.
Serve hot with additional soy sauce and sriracha sauce if desired.