Japanese Knotweed Recipes: The Heart of Seasonal Dining

At The Chef’s Garden and Culinary Vegetable Institute, we embrace seasonal dining, appreciating each of the seasons for what they have to offer our palates. Because we’re fortunate enough to work the soil every single day throughout the year, we recognize how the designations of spring, summer, fall, and winter are really just broad categories that encompass the beautiful seasonal nuances that Mother Nature gifts us with each year.

For example, Japanese culture traditionally celebrates 72 poetic micro seasons, with May 15-20th serving as the “bamboo shoots sprout season.”

It isn’t surprising, then, that knotweed—a Japanese vegetable that resembles bamboo—has been flourishing right now. “Although this is considered to be an invasive species in many parts of the world,” Culinary Vegetable Institute Chef Tristan Acevedo says, “you can use knotweed to offer acidic contributions to your food. It’s slightly earthy and distinctly sour, and easy to cook with.”

To help, we’ve provided four delicious Japanese knotweed recipes—and, for a short period of time, this fleeting ingredient may be included in your Best of the Season box of farm-fresh vegetables. “It tastes deliciously sour like rhubarb,” Culinary Vegetable Institute Chef Jamie Simpson says, “with a texture like asparagus if it were hollow. In the Best of the Season box, the shoots are cut to asparagus length.”

General Japanese Knotweed Uses

“Wash it like you would any vegetable,” Chef Tristan says, “then use it in any place where lemon or rhubarb would be appropriate. Sliced and seared, it will complement a delicate piece of fish or offer a counterpoint to a rich braise. In desserts, knotweed offers balance to otherwise sweet recipes. It can be sliced into thin rounds and then quickly pickled, incorporated into a medley of vegetables, or substituted directly for rhubarb in jams, jellies, pies, and cobblers. Knotweed can be eaten raw or cooked and is a natural fit in salads. For a more tender preparation, peel knotweed to remove the outer skin. At this point, it can be treated much like asparagus.”

Now, here are the Japanese Knotweed recipes!

Knotweed-Rhubarb-Bars

Knotweed, Strawberry, and Rhubarb Crumble Bars

You can make these bars to enjoy them for breakfast, lunch, or dinner. They’re not too sweet and what sugar there is actually balances nicely with the additional of knotweed, rhubarb, lemon, and strawberries. You can dig in while it’s still warm but be careful not to burn yourself with a bubbling middle layer.

Servings: 12 bars

Source: Culinary Vegetable Institute

Ingredients

Base Layer

  • 1 1/2 cups all-purpose flour
  • 1/3 cup of sugar
  • 1 1/2 tsp baking powder
  • 1 stick of unsalted butter, cubed and chilled
  • 1 medium egg
  • 1 pinch of kosher salt

Middle Layer

  • 2 cups sliced strawberries, 1/2 inch thick
  • 2 cups sliced rhubarb, 1/2 inch thick
  • 2 cups of sliced knotweed, 1/2 inch thick
  • 8 tsp cornstarch
  • 3/4 cup granulated sugar (100 grams)
  • 2 lemons, zested and juiced

Top Layer

  • 1 cup all-purpose flour
  • 3/4 cup of rolled oats
  • 1/2 cup granulated sugar
  • 1/4 cup packed light brown sugar
  • 1/2 tsp of kosher salt
  • 1 stick of unsalted butter, cubed, then softened

Directions

Preheat the oven to 375F. Also prepare a 9×9 or 9×13-inch baking dish by lining it with greased parchment and buttering the sides.

For the Base Layer

Combine all of the dry ingredients and the lemon zest. Use a fork to cut in the chilled cubes of butter until the mix is clumpy and the pieces of butter are the size of smashed peas. Beat the egg and add it to the mix, continuing to cut in until a handful of the mixture stays together when squeezed.

Transfer the mix to the prepared baking dish and press it evenly into the base. Bake this layer by itself for about 20 minutes while you prepare the rest of the ingredients.

 For the Middle Layer

Whisk together the sugar and cornstarch, then add the remaining ingredients for the middle layer and mix. When well combined, transfer these ingredients to a small sauce pot and bring to a simmer for 60 seconds. Remove from the heat and transfer it to the baking dish and spread it evenly over the warm base layer.

 For the Top Layer

Combine all of the dry ingredients in a mixing bowl. Use your hands to mix in the softened butter. The mixture should clump coarsely and irregularly. Sprinkle this mixture in an even layer over the contents of the baking dish and transfer it to the oven. Bake for about one hour, ensuring that you rotate or switch racks in the oven so that the top layer becomes golden brown but does not burn.

Remove from the oven and allow it to cool on the counter for several hours before portioning and refrigerating.

 

Seared-Knotweed-Salad

Seared Knotweed Salad

This dish shows just how versatile Japanese knotweed can be. In savory applications with mustard, seared fennel, and apples, knotweed is right at home. It grills or sautés well. Incorporate this vegetable into any stir fry, as well. 

Servings: 2 as a meal, 4 as a side

Source: Culinary Vegetable Institute

 Ingredients

  • 1/2 lb of knotweed, washed
  • 1 fennel bulb, quartered then sliced lengthwise, 1/8” thick
  • 1 crisp apple (any variety), quartered, core removed, then thinly sliced
  • 1/3 envelope Best of the Day Micro Herbs
  • 2 tbsp Neutral oil for searing
  • Salt to taste

Vinaigrette

  • 1/2 shallot, minced
  • 2 tbsp honey
  • 2 tbsp Dijon or whole grain mustard
  • 1 lemon, juiced, and zested
  • 1/3 cup olive oil
  • Salt to taste

Directions

Combine all of the ingredients except the salt and olive oil in a small mixing bowl. Whisk them together before streaming in and emulsifying the olive oil. Add salt to taste and reserve.

Prepare the dressing; it can be made up to a day in advance and removed from the fridge an hour before use.

Set up a cutting board. Wash the knotweed, fennel, and apple, and pat them dry.

To prepare the knotweed, cut it at a bias into one-inch long sections so that it resembles small penne.

For the fennel, quarter it, then remove most of the core but leave enough so that the layers of fennel remain attached. Slice it lengthwise into slices that are 1/8-inch thick. If you have one, use a mandoline to simplify the job.

Quarter the apple and remove any seeds or core. Again, using a mandoline if you have one, slice the apple and store the apple slices in water so they do not brown.

Preheat a non-stick pan or cast-iron skillet on medium heat until it is hot enough to sear. Add a splash of oil and the fennel slices to the pan. Brown them until they just begin to wilt but retain some crunch. Transfer them to a mixing bowl and do the same with the knotweed. While the knotweed is cooking, drain the apple slices and add them to the mixing bowl. When the Japanese knotweed is ready, about one to two minutes, add it to the mixing bowl and toss the ingredients to combine them. Dress the salad lightly and season it with salt before transferring it to a warmed bowl. Finish with 1/3 of an envelope or so of micro herbs. Serve any additional dressing on the side.

Knotweed-Vodka-Tonic

Knotweed Vodka

Servings: 10 ounces of Knotweed Vodka

 Ingredients

  • 1/2 lb knotweed, sliced into rounds
  • 1 1/4 cups vodka
  • 1/4 cup sugar (optional, if you like sweet vodka)

Directions

Combine all ingredients in a bottle or glass mason jar and allow it to sit at room temperature for a few weeks, up to a month. Taste it every few days and, when it’s to your liking, it’s ready to use.

Picked-Knotweed

Cold-Pickled Knotweed

Servings: 1-quart jar

Source: Culinary Vegetable Institute

Ingredients

  • 3 cups of water
  • 3/4 cup of apple cider or champagne vinegar
  • 1 1/2 tsp salt
  • 1/3 cup sugar
  • 15 pearl onions, peeled and quartered
  • 3 cups of sliced knotweed, thin scallion-like bias cuts (1/8th inch)

Directions

In a 2-quart saucepot, combine the pearl onions, vinegar, sugar, water, and salt. Bring the liquid to a boil and ensure that all of the sugar dissolves. Simmer the contents of the pot for about two minutes, then remove it from the heat and allow it to cool to room temperature. In a Tupperware container or 1-quart mason jar, add the sliced knotweed and cover fully with the pearl onions and brine. Place this container in your refrigerator for at least 24 hours. After this period of rest, the pickles are ready to use.

Remember that, for a short period of time, Japanese knotweed is being added to the Best of the Season box of farm-fresh vegetables