In a heavy bottomed or cast iron pot, heat butter and olive oil. Add the potatoes and onions and cook over medium heat until vegetables began to soften, about 5 minutes. Add the celery and the garlic, cook an additional minute.
Add the flour to the pot, stirring to coat vegetables. Stir in the wine, water and chicken broth. Bring to a boil. Reduce heat to a low and simmer for 10 minutes.
After 10 minutes, remove soup from heat. Stir in corn, crab meat and half and half until thoroughly combined. Return to low heat until contents comes to a simmer. Ladle into warmed bowls and Top with parsley or croutons and serve. Salt to taste, if needed.