Knotweed is an invasive thug of a creeping rhizome. It grows up to 5 feet tall and spreads its tendrils beneath our garden soil in an unrelenting onslaught, having gone so far as to slither its way in between the tightly fitted stones of our 200 year old well that's kept a tight water seal until it met the sprouting menace. There are strict laws governing the use and transport of knotweed in the UK, its ability to jump ship and burrow into neighboring gardens is legendary. The evil bugger is gleefully infesting these United States from Central Park to our very own Freegrace Tavern and can grow inches in a day. And while eradicating this pestilence is nigh impossible, one way of controlling it is to eat the tender shoots as they pop their ruby heads from the ground. The taste is lovely, part lemon part herbaceous lightness. Think of fresh, none invasive goodies like rhubarb for a taste comparison, although the plant is actually not a member of the rhubarb family but is a cousin of buckwheat. By infusing this cake with vanilla, the herbaceousness becomes lush and elegant. The semolina gives a satisfying crunch and heartiness while the cranberry is a pop of sweet and tart.
Japanese knotweed is at its tastiest when it's just begun to sprout and is still flexible at a stage where it's called "wild rhubarb" (in Vermont, early to mid May), otherwise the stalks become woody as they grow taller. And by snipping the early stalks before they go to flower and spread their seed you do the landscape, and your belly, a huge service.
(Makes about 30 small muffins)
FOR THE CRUMBLE
1 1/4 cups all purpose flour
4 ounces unsalted butter, melted
1/4 cup granulated sugar
1/4 cup brown sugar
PROCEDURE FOR CRUMBLE
•In a mixing bowl, stir together all ingredients until the mixture comes together in small clumps, use your hands if you need to.
FOR THE CAKE BATTER
1 cup semolina flour
2 cups all purpose flour
2 cups sugar
8 ounces (2 sticks) unsalted butter
5 large eggs, room temperature
1 tablespoon baking powder
1 teaspoon salt
1 tablespoon vanilla bean paste (I use Nielsen-Massey)
1 1/4 cup buttermilk
1 1/2 cups Japanese knotweed, diced (about 5 foot-long stalks)
1/2 cup dried cranberries (can substitute dried currants)
PROCEDURE FOR THE CAKE BATTER
•Preheat oven to 350º.
•Strip the leaves from the stalks and dice the stalks in 1/4 to 1/2 inch pieces.
•In the bowl of a stand mixer fit with the paddle attachment, cream together the butter and sugar until very light and fluffy.
•Add eggs, one at a time, scraping the bowl after each addition, until well combined. Add the vanilla bean paste.
•In a large bowl, whisk together the semolina flour, all purpose flour, salt and baking powder.
•With the mixer running on low, add 1/3 of the flour mixture and then add 1/2 of the buttermilk. Continue alternating between the flour and buttermilk mixture until completely combined.
•Fold in the dried cranberries and diced knotweed.
•Divide evenly among muffin cups, filling just a little more than half way.
•Spinkle the tops of each muffing with about 1 tablespoon of crumble.
•Bake for 1/2 hour or until the cake gently springs back when gently poked.