Cook the wild rice blend according to the instructions on the package. Drain and set aside. Season with salt and pepper to taste. Cover with a lid to keep warm.
Heat a nonstick pan on medium heat. Once hot, add the oil. Saute the garlic and onion until fragrant golden brown. Add the shrimp and saute until pink, then remove the shrimp and set aside. (Doesn't have to be fully cooked yet, shrimp shrinks the longer it's cooked)
Stir in the wine and lemon juice. Simmer until it mostly evaporates down to 1 to 2 tablespoons.
Stir in the broth, butter, and scallions. Bring to a low simmer to build flavor. Season with salt and pepper to taste. (Add more lemon if needed to provide brightness but not overpowering lemon flavor)
Once the sauce is flavorful and balanced, stir in the cornstarch slurry a little at a time until the sauce is thickened to a creamy consistency. Add the shrimp back to the pan and simmer until firm.
Serve with wild rice and bread. Garnish with parsley and red pepper flakes (if using).