In a small bowl, mix together all the ingredients for the sauce.

Place the prepared shrimp in a medium bowl and add ¼ of the sauce. Allow the shrimp and sauce to marinate for 30 minutes.

Add cornstarch to the remaining sauce.

In a large pan over medium-high heat, add olive oil and onion. Cook for 3 minutes, then add broccoli. Cook for an additional 5 minutes, seasoning with salt, pepper, and garlic powder. Remove from the pan.

Quickly add butter to the pan and cook shrimp in a single layer. You may need to cook the shrimp in two batches. Cook shrimp for 2-3 minutes per side. Remove from the pan.

Reduce heat to medium-low. Add the set-aside sauce/cornstarch to the pan and bring to a simmer. As soon as the sauce starts to thick turn off the heat.

Add shrimp, broccoli, and onions back to the pan. Toss to coat evenly in the delicious sauce.

Serve over rice and top with chopped green onions and sesame seeds.