Cauliflower Steak Sandwiches With Red Pepper Aioli

Roasted cauliflower “steaks” make a satisfying and filling vegetarian sandwich. This recipe boosts the flavor factor with a quick and easy aioli sauce, sliced tomatoes, and spicy arugula.

Best Cauliflower Steak Sandwich arugula
Sally Vargas

When thick slabs of cauliflower, called steaks, are roasted until golden, they become the stars of this vegetarian sandwich.

How to Turn Cauliflower Into a 5-Star Sandwich

When cauliflower steaks are baked at high heat, they take on a sweet, irresistible succulence in the center, with crispy golden edges. You hardly need anything else, but of course, there’s more.

A red pepper aioli (read: garlicky mayonnaise) guilds the lily, and layered with tomatoes between two slices of tangy sourdough toast, these steaks give you a sandwich to cheer about.

Easy Cauliflower Steak Sandwich - open faced sandwich with sliced tomatos, crusty sourdough bread and red pepper aioli
Sally Vargas

How Do You Cut Cauliflower to Make Steaks?

To cut cauliflower steaks, use a large chef’s knife to carve off the bottom leaves and base of the head so it stands upright.

Stand it on a cutting board, and starting at one side of the head, cut it into slices that are about 1/2-inch thick. Some of the cauliflower florets will not be attached to the base—I call them scraps—they are still good to roast or to make cauliflower rice.

Flat, smaller pieces, can also be roasted with the large steaks—they can be used to build your sandwich. If the head is very large, cut it in half, lay it with the flat side down, and slice across it to make large half-steaks.

What Is Aioli?

In the old French tradition, aioli simply meant a hefty amount of garlic mashed within an inch of its life in a mortar, with droplets of olive oil added painstakingly to form a fluffy paste.

Egg yolks and lemon juice came along more recently. Now you have an emulsion akin to mayonnaise. Aioli is commonly thought of as simply garlicky mayo, sometimes with different flavorings, though you’ll get lots of arguments about its origins and local variations (regions of Spain and Italy being fierce contenders).

Easy Cauliflower Steak Sandwich arugula
Sally Vargas

How to Make Shortcut Aioli

This aioli is made with roasted sweet red pepper and a hint of hot red pepper flake to give it a little spice.

Rather than starting with garlic and egg yolks to make a mayonnaise-like aioli, I’ve taken a few shortcuts to make your life (and mine) easier, specifically by using store-bought mayonnaise. This means you can substitute dairy-free mayonnaise if you are vegan or lactose intolerant.

I’ve provided instructions on how to roast a pepper for this aioli, but you can skip that step and substitute peppers from a jar if you like. All the ingredients for the aioli are whirled in a food processor to make a creamy sauce, slightly thinner than mayonnaise.

I advocate using only one clove of garlic, because the flavor intensifies as it sits, but if you are a true garlic lover, you could add more. You will most likely have some sauce left over, so save it to drizzle over fish, hard-boiled eggs, grilled chicken, or roasted vegetables.

How to Store Aioli

If you have extra aioli, you can store it for up to a week in the refrigerator. Like store-bought mayonnaise, it should keep well, but not as long as a jar of mayonnaise, because you have added red pepper and garlic. Like mayonnaise, aioli doesn’t do well in the freezer, because it tends to separate.

Need More Cauliflower in Your Life?

Cauliflower Steak Sandwiches With Red Pepper Aioli

Prep Time 15 mins
Cook Time 35 mins
Total Time 50 mins
Servings 4 sandwiches


  • For the aioli:
  • 1 clove garlic, thinly sliced
  • 2 tablespoons lemon juice
  • Pinch of salt
  • 3/4 cup roasted red peppers from a jar, drained and diced
  • 1/2 cup mayonnaise (any kind)
  • 1/4 teaspoon Maras, Aleppo, or other red pepper flakes
  • For the sandwiches:
  • 2 medium or 1 very large head of cauliflower
  • 3 to 4 tablespoons olive oil
  • 1/2 teaspoon salt
  • 1/8 teaspoon ground black pepper
  • 1 teaspoon smoked paprika
  • 8 slices sourdough bread
  • 2 large tomatoes, thickly sliced
  • 2 handfuls arugula, or other greens of your choice, such as crisp lettuce

Special Equipment

  • Food processor


  1. Preheat the oven to 450ºF:

    Spray or brush a rimmed baking sheet with olive oil.

  2. Make the aioli:

    In a food processor, combine the garlic, lemon juice, and a pinch of salt. Let the garlic soak for about 5 minutes to soften the garlic’s raw harshness. Add the roasted peppers and puree until smooth. Add the mayonnaise and red pepper flakes and pulse to mix. The consistency of the aioli should be slightly thinner than mayonnaise. Taste and add more red pepper flakes, if you like.

  3. Slice the cauliflower steaks:

    Leaving the core intact, trim a sliver from the bottom of the stem end of the cauliflower and remove the leaves. Stand the cauliflower upright on its base. With a large knife, cut it into 1/2-inch thick steaks. You should get at least 4 slices that hold together.

    You will have some “scraps”—slices of cauliflower that are not attached to the base. If they are flat, you can roast them with the steaks and use them to build your sandwich. Don’t throw other scraps away! Either roast them on a separate baking sheet when you roast the steaks, or save them for cauliflower rice.

    Vegan Cauliflower Sandwich Recipe - a head of cauliflower being sliced on a wooden cutting board
    Sally Vargas
    Roasted Cauliflower Steak with Paprika - cauliflower steaks sliced on a cutting board
    Sally Vargas
  4. Roast the cauliflower:

    Brush both sides of the steaks and the flat scraps with oil. Sprinkle both sides generously with salt and pepper. Set them on the baking sheet, and sprinkle lightly with the paprika.

    Cover the cauliflower with foil and roast for 10 minutes. (This allows the cauliflower to steam briefly and soften in the center.) Remove the pan from the oven and remove the foil. Return it to the oven and roast for 10 minutes longer, or until the cauliflower begins to brown.

    Carefully turn the steaks over, sprinkle with more paprika, and bake for an additional 8 to 10 minutes, or until golden and tender when you insert the tip of a knife into the steak. Remove from the oven and set aside. Total roasting time is about 30 minutes.

    Roasted Cauliflower Steak with Paprika - cauliflower steaks spread out on a pan
    Sally Vargas
  5. Toast the bread:

    Set your oven to broil. On a baking sheet, spread the bread slices. Brush them on both sides with oil. Broil for 1 to 2 minutes on each side, or until toasted on the outside but still slightly soft in the middle. Watch carefully to keep them from burning!

  6. Assemble the sandwiches:

    Spread the aioli on each slice of bread. On each of 4 slices, set the cauliflower on top. Top each with tomato slices and arugula. Cover each with a second slice of bread. Cut the sandwiches in half and serve.