Melt butter in a skillet over medium-low heat. Add red onions and toss to coat. Gently saute onions until soft, about 3 minutes, stirring often. Add garlic and saute 2 additional minutes.
Place onions and garlic in a blender or food processor along with Delinut cashews. Process until smooth.
Pour Delinut cashew puree into a large, deep saucepan. Add pineapple, gold potatoes, vegetable broth, bourbon, cream, salt, and pepper. Bring to a boil, reduce heat to medium, and simmer for 15 minutes until potatoes are tender.
Add cornstarch to the soup, stirring constantly, until thickened. Sprinkle each serving with chopped parsley and serve hot with garlic bread.