Salmon penne with vodka sauce

Ingredients

• 1/2 cup butter
• 1 onion, diced
• 1 cup vodka
• 2 (28 ounce) cans crushed tomatoes
• 2 teaspoons oregano
• 1/4 teaspoon cayenne pepper
• 2 tablespoons sugar
• 1 pint heavy cream
• 1 pound of skinless salmon fillets
• 12 ounces of whole wheat penne pasta