Whisk together all ingredients for sauce, set aside
Heat a large non-stick skillet over medium-high heat. When hot, add one tablespoon of oil. Add the shrimp and season with salt and pepper. Cook 1-2 minutes per side, until pink. Be careful not to overcook. Remove shrimp from pan.
Return pan to heat and add the other tablespoon of oil. Add the onion and sauté for about 5 minutes, until softened and starting to turn golden. Add the broccoli, cook, stirring often until bright green and crisp tender, about 7 minutes.
Return shrimp to pan. Add the sauce and stir until everything is coated and sauce has thickened, about 7 minute.