Mince the garlic. Heat the olive oil over medium heat. Add the garlic and fennel seeds and cook for about 1 minute until fragrant and the garlic is golden (do not allow to brown).
Turn the heat to medium low. Add the canned tomatoes, tomato paste, 1/4 cup of the heavy cream, the half onion, the oregano, and the salt. Simmer 20 to 30 minutes until the sauce is thickened.
When thickened, remove the half onion and stir in remaining 2 tablespoons heavy cream. Taste; if you didn’t use fire roasted tomatoes and the flavor is acidic, add a few teaspoons sugar and taste again. Serve with 1 pound pasta. If desired, serve with Parmesan shavings and chopped fresh basil. Leftover sauce stores refrigerated for up to 1 week.