In a large bowl combine the cornstarch, salt, black pepper, and cayenne pepper; whisk until thoroughly combined.
Heat 1 inch of vegetable oil in a heavy pan, cast iron or a Dutch oven to 360 degrees.
While oil is heating, add shrimp to bowl with cornstarch mixture, toss with rubber spatula to coat shrimp.
Fry shrimp in batches of 6, turning shrimp after 60 seconds, frying an additional 60 seconds or until shrimp are cooked through.
Remove shrimp from oil, and place on a paper towel lined cookie sheet or wire rack.
Melt butter in saucepan over low heat, or in the microwave.
In a large bowl add melted butter, hot sauce and sugar, whisk until combined.
Toss shrimp in prepared buffalo sauce until completely coated.
Serve with prepared ranch dressing or additional buffalo sauce.
