Fermented Nduja subs on a plate.

Recipe: Tomato 'Ndjua, Avocado & Fermented Jalapeño Kraut Subs

Root vegetables from last season are still among us. Grab any red onions, parsnips, carrots and garlic you have lying around and put them to good use by transforming them into a jar of fermented goodness.

The featured fermented jalapeño kraut can be enjoyed on its own but is specifically designed to be used as a go-to sandwich topping. It contributes crunch, tang and a hint of spice, and its lengthy refrigerated shelf life will have you reaching for it in a pinch when you don’t have lettuce on hand.

This sub sandwich highlights the fermented jalapeño kraut alongside sliced avocado, red onion and a tomato iteration of ‘nduja. ’Nduja is a spicy Italian sausage spread that adds a big hit of flavor in any application. This particular tomato version consists of simmering sundried tomatoes, sliced onion, garlic and paprika in olive oil and then blending them with brown sugar, miso paste and kraut brine. It helps round out a well-crafted sandwich that is filled to the brim with contrasting flavor and textural notes.

What’s Good to Know with Chef Olivia:

  • When fermenting jalapeños, leave the seeds and pith intact, or the peppers will become relatively flavorless.
  • Using the kraut brine to blend the tomato ‘nduja not only adds flavor but is also resourceful and makes the spread contain probiotic qualities.
  • Utilizing root vegetables such as carrots, parsnips and red onion helps build complexity as the ferment evolves because of their natural built-in sugar and carbohydrate-rich starch molecular makeup.
  • Adding raw apple cider vinegar to the ferment helps drop the pH faster, which in turn speeds up the fermentation process while helping the vegetables retain their crunch.
  • Using a variety of vegetables in your batch of kraut lends attractive hues of purple, orange and green to your jar.


Tomato 'Ndjua, Avocado & Fermented Jalapeño Kraut Subs

Yield:1 gallon-sized jar of Fermented Jalapeño Kraut; 2 1/4 cups ‘Nduja; 6 Sub Sandwiches



For the Fermented Jalapeño Kraut:

  • 2 carrots, peeled and cut into strips
  • 2 parsnips, peeled and cut into strips
  • 1 green cabbage, shredded (outer leaves reserved)
  • 6 garlic cloves, smashed
  • 1 red onion, cut into thin slices
  • 6 jalapeños, cut into thin strips (with seeds and pith intact)
  • 3 tablespoons salt
  • 1/4 cup brown sugar
  • 1/4 cup raw apple cider vinegar

For the ‘Nduja and Assembly:

  • 1/3 cup olive oil
  • 1 yellow onion, sliced
  • 2 teaspoons sea salt, or to taste
  • 6 garlic cloves, smashed
  • 1 cup sundried tomatoes, chopped
  • 2 teaspoons paprika
  • 3 tablespoons miso paste
  • 2 tablespoons brown sugar
  • 1/2 cup fermented sandwich jalapeño kraut brine
  • 1 baguette, cut into 6 pieces
  • 2 ripe avocados, sliced
  • 1 red onion, sliced
  • 1 cup fermented jalapeño kraut


For the Fermented Jalapeño Kraut:

  1. Add cut carrots, parsnips, cabbage, garlic cloves, red onion, jalapeños, salt and sugar to a large bowl. Massage for a few minutes and fold in apple cider vinegar.
  2. Pack mixture into a gallon-sized, sterilized glass jar, along with any residual liquid. 
  3. Cover with reserved outer cabbage leaves and place in fermentation weight.
  4. Cover with water until level reaches 1 inch below the lower glass rim. 
  5. Fasten jar with airlock lid and ferment at room temperature for 7 days.
  6. Transfer to refrigerator for extended storage.

For the ‘Nduja and Assembly:

  1. Warm olive oil in a wide pan over medium heat.
  2. Add sliced onion, salt, smashed garlic and chopped sundried tomatoes.
  3. Cook for 2 minutes. Fold in paprika, miso paste and brown sugar.
  4. Blend on low with jalapeño kraut brine, so the mixture retains some texture.
  5. Cool before serving.
  6. Split baguette pieces by cutting from the top of the bread into the center.
  7. Schmear smokey tomato ‘nduja onto bread.
  8. Top with avocado slices, red onion slices and fermented jalapeño kraut.

More fermented recipes from Chef Olivia:

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