Slow Cooker Tomato Sauce with Fennel

slow cooker tomato sauce with fennel

I really relied on my slow cooker to get me through the winter. I use it almost every day to cook beans and other things. It’s easy for me to accidentally forget to make dinner for my family when I’m working like crazy. Isn’t that ironic? So much food around all the time for various photo and recipe development projects and I still forget to make food for my family. Ha! Well, this slow cooker tomato sauce with fennel has been a lifesaver the past week. My kids haven’t complained about eating pasta again, and there’s still a bit in the fridge, so I think it was a pretty big success.

I love springtime veggies. Fennel is usually available year round, but the season peaks between November and March. I eat it whenever I can because it’s one of my favorite veggies. Usually I like it fresh in salads, but I also love it cooked, like in this tomato sauce.

slow cooker vegan tomato sauce with fennel

The idea for this sauce came from that tomato sauce recipe that has been ever-popular in Blogland for the past few years. The original recipe comes from Essentials of Classic Italian Cooking, by Marcella HazanWhole tomatoes and a halved onion are cooked with a good amount of butter for quite a long time. The tomatoes are broken up with a wooden spoon and before serving, the onion is removed and discarded. When I started making that recipe a few years ago, I never discarded the onion. We like onions quite a lot, so I used my immersion blender to break it up a bit. Anyway, that tomato sauce is AMAZING. Like the best sauce you’ll ever taste. And this one I’ve come up with takes cues from that sauce, but adds in fennel and uses olive oil to make it dairy-free.

vegan slow cooker tomato sauce with fennel

The result was amazing! I’ve made it several times and I completely, 100% love it. The fennel adds another depth of flavor similar to adding sausage, only not. You know? After cooking for that long time in the slow cooker, the tomato sauce is just as amazing as the original recipe. The onions and fennel are butter-soft and practically melt in your mouth. I leave it a little chunkier because that’s how we like it, but it could be pureed a bit for a smoother sauce.

Now, we like it over pasta, but it would be good anywhere you use tomato sauce – over polenta or rice (or another grain), in lasagna, with eggs, even pureed into a soup.

Here are some other springtime recipes using fennel:
Caramelized Fennel and Onion Pizza from Love and Olive Oil
Roasted Kale and Fennel Salad with Avocado Caesar Dressing from Foodie Crush
Fennel and Pea Soup from A Brown Table
Blood Orange and Fennel Salad from Taste Love and Nourish
Caramelized Fennel and Apple Tart from Foxes Love Lemons
Crispy Skinned Barramundi with Citrus Fennel Salad from Jelly Toast
Fennel and Cabbage Slaw from Simply Scratch
Fennel Walnut Chicken Salad from All Day I Dream About Food
Beet and Fennel Soup from Love and Olive Oil
Millet Pilaf with Roasted Carrot and Fennel from An Edible Mosaic

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Slow Cooked Fennel Tomato Sauce over Zucchini Noodles

A flavorful, slow cooked tomato sauce made with fennel.

  • Total Time: 8 hours 20 mins
  • Yield: 12 1x


  • 24 Tablespoons extra virgin olive oil
  • 2 large fennel bulbs
  • 1 large onion, diced
  • 6 cloves garlic, chopped
  • 2 (28 ounce) cans organic diced or whole tomatoes
  • 2 (4 ounce) cans organic tomato paste


  1. To prepare fennel – cut green stalks from bulb. Cut in half and remove core by cutting a V into each half where the core is. Lay the fennel cut-side down and slice crosswise, then dice. Set aside.
  2. Heat the olive oil in a skillet, or slow cooker if yours is stovetop safe. Add the onion, fennel, and garlic. Season with a little salt. Cook, stirring frequently until the vegetables start to soften. Transfer to a slow cooker, if not already using one, and add the tomatoes and paste.
  3. Cook on LOW heat for 8-10 hours, or HIGH for 5-6 hours. The sauce will be done when the fennel is butter-soft and tender.
  4. Serve over pasta, polenta, rice, zucchini noodles, or quinoa.


-I have a BIG slow cooker, so I make big batches of sauce and freeze half and use the rest throughout the week.
-This sauce would be great in lasagna as well.
-If you’re not a fan of fennel, use an extra onion.

  • Author: Lindsey Johnson
  • Prep Time: 20 mins
  • Cook Time: 8 hours
  • Category: Main, sauce
  • Cuisine: Italian

Disclosure: This post contains affiliate links.

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  1. This sauce is so lovely! I love the flavor of fennel. I’m looking forward to giving this a try! Thanks so much for including my salad in your fennel roundup!

  2. Wow is fennel really your favorite veggie? You’re so mature Lindsey. I’m still working on liking regular stuff like broccoli. :) I’ve never cooked with fennel, (I know, I know, the shame) but I do notice when it is in sausage or in a sauce like this, and I like it. I should try this out, you mentioning trying it over polenta has me craving it. Yum!

    1. Ha! You’re so funny. It’s taken me a long time. I used to hate the flavor of black licorice, but fennel helped me change my mind. I really do love it a lot. I think I like it raw a tad bit more than cooked. Do try it with polenta! And I’m so honored you were my 2000th follower on Twitter. :)

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