If your shrimp is frozen, thaw it first by placing in a colander and running cool water over it until thawed (this only takes a few minutes).
Finely dice the onion and place it in the bottom of the rice cooker along with the frozen peas (I did not thaw my peas). Add the uncooked rice, minced garlic, and grated ginger. Stir these ingredients together.
Add the shrimp to the top of the rice mixture, then pour in 2 cups water. Close the lid and set the cooker to the “white rice” setting. The rice cooker will begin to heat and once the contents inside reach the appropriate temperature, it will begin to count down the cooking time (12 minutes for my model).
Once the rice cooker finishes its cooking cycle, let it rest for an additional 5-10 minutes on the keep warm cycle before opening the lid. While waiting, stir together the soy sauce and brown sugar.
Finally, open the lid and pour the soy sauce mixture over the contents in the rice cooker. Use a rice paddle to gently fold the sauce into the rice. Serve hot, with sriracha or sliced green onions if desired.