Melt butter in a large pan over medium heat. Add onion and bacon and cook until bacon is crispy and onion is soft and golden brown, about 6 minutes.
Meanwhile, drain clams, reserving juice and clams separately. Add the juice and white wine to pan. Bring to a simmer, scraping the bottom for any browned bits.
Add potatoes and salt. Return to boil, reduce heat and simmer, partially covered, until potatoes are tender, about 25 minutes.
Add tomatoes and garlic powder and simmer for another 5 minutes, or until thoroughly heated.
Stir in reserved clams, milk and cream. Heat until hot, but do not boil. Serve immediately.
Servings: 6