Crockpot Onion Marinara sauce

All you need are basic pantry ingredients to make this delicious marinara sauce: canned chopped tomatoes, onions from your Oddbox, garlic , dried oregano and salt and pepper. This sauce is simple, but you can add any extras you like – capers, olives, spices, or even a dash of wine. It freezes well, and can be used as pasta sauce, spread on toast, as dipping sauce or even on pizzas.


  • No red onions? Use white onions or shallots instead. 
  • No dried oregano? Swap for thyme or rosemary. 

Prep time: 10 minutes

Cook time: 120 minutes

Total time: 130 minutes

Servings: 6


3 Onions (chopped )

3 Garlic cloves (chopped )

2 Can chopped tomatoes

1 tbsp Oregano

200 ml Water

Salt & pepper


  1. In the slow cooker: Add all of the ingredients into the bowl of your slow cooker. Place the lid on, and cook on low for 6-8 hours or on high for 3-4 hours. Transfer the sauce to a blender (or use a hand belnder) to puree it until smooth. Season to taste and enjoy!
  2. On the stove: Place a saucepan over a medium heat. Add all of the ingredients in the pan. Put the lid on and simmer for 35 minutes, stirring often. Take off the lid and cook for another 10-15 minutes, until the sauce has thickened. Use a hand mixer or food processor to blend the sauce until smooth. Season to taste and enjoy! 
  3. To serve: bring a saucepan of salted water to a boil and cook your pasta until al dente. Drain and divide between plates or bowl. Top with the sauce, fresh basil and grated parmesan. You can also use the marinara sauce as pizza base sauce.
Oddbox image

How to store

Store in an airtight container (or jars) in the fridge for up to 3 days, or in the freezer for up to 2 months. We love to use ice cube trays to store perfectly portioned sauced in the freezer.

Oddbox Fruit and Vegetable box