Bison Burger With Cajun Bourbon Mayo Recipe

Name: Bison Burger With Cajun Bourbon Mayo Recipe
Ingredients: 2 small Spanish onions, very thinly sliced; 2 cups buttermilk; 2 cups flour; 1 teaspoon garlic powder; 1 teaspoon paprika; ½ teaspoon salt; ½ teaspoon pepper; 1 quart vegetable or canola oil, for frying; ½ cup mayonnaise; 2 cloves garlic, grated; 1 tablespoon bourbon; 2 teaspoons Cajun seasoning; ½ teaspoon lemon juice; 1 pound ground bison; 1 teaspoon salt; 1 teaspoon cracked black pepper; 2 tablespoons grapeseed oil, for cooking; 4 brioche buns