Miso is a fermented soy bean paste that is loaded with all things savory, sweet, and deliciously right about East Asian cuisine. I know it may feel a bit like an over-commitment when you pick up that tub from the grocery store, but go with me on this one. The further down the miso rabbit hole you dig, the more you'll wonder just how it is you got so far, for so long, without it.
Place a large skillet over high heat with the oil. Add the shrimp to the skillet and stir-fry until the shrimp just begin to turn pink, 2 to 3 minutes. Add the garlic, bell pepper, carrots and snow peas to the pan and continue stir-frying until the vegetables just begin to tenderize, about 1 minute. Add the reserved sauce to the skillet and stir-fry until the shrimp is cooked through and the sauce has thickened, 2 to 3 minutes.
Adjust the seasoning with soy sauce and sriracha. Serve the stir-fry over the steamed rice garnished with the bean sprouts.