Celery Soup with Peanut Crumble and Pickled Grapes

Ingredients

• For the pickled grapes:
• 2/3 cup sherry vinegar
• 1/3 cup sugar
• 1 tablespoon kosher salt
• 1 small bunch green or red seedless grapes, peeled or halved
• For the peanut crumble:
• 1/2 cup creamy unsweetened peanut butter
• 2 tablespoons unsalted butter, softened
• 1/2 cup all-purpose flour
• 6 1/2 tablespoons confectioners' sugar
• 2 tablespoons cornstarch
• 1 1/2 teaspoons kosher salt
• 3/4 teaspoon dried dill
• 1/2 teaspoon onion powder
• 1/4 teaspoon cayenne pepper
• For the celery soup:
• 2 tablespoons unsalted butter
• 1 small yellow onion, diced
• 1 bunch celery, cut into 1-inch chunks, leaves reserved
• 1 medium celery root, peeled and cut into 1-inch chunks
• 1 small tart apple, such as Honeycrisp, peeled, cored, and cut into 1-inch chunks
• Kosher salt
• 1 quart vegetable stock or water, plus more to adjust
• 1/3 cup heavy cream

Directions

1. For the pickled grapes, combine the sherry vinegar, sugar, salt, and 1 cup (240ml) water in a small saucepan. Warm the mixture just until it begins to simmer and the sugar and salt have dissolved, then take it off the heat and let it cool. Put the grapes in a nonreactive heatproof bowl, pour the cooled brine over them, and press a paper towel onto the surface so the grapes stay under the liquid. Leave them at room temperature for at least 30 minutes, though overnight is even better.
2. Meanwhile, make the peanut crumble. Heat the oven to 350 degrees F (180 degrees C). In a medium bowl, add the peanut butter, butter, flour, confectioners' sugar, cornstarch, salt, dill, onion powder, and cayenne pepper. Use your fingers to work everything together until the mixture is evenly blended and breaks into small clumps.
3. Scatter the crumble in an even layer on a rimmed baking sheet lined with parchment or foil. Bake until it is golden all over, about 15 minutes, stirring it once partway through. Leave it to cool.
4. Meanwhile, start the celery soup. Melt the butter in a Dutch oven or large saucepan over medium heat until it bubbles and turns foamy. Add the onion, celery, celery root, apple, and a large pinch of salt, then cook, stirring often, until the vegetables have softened without browning, about 5 minutes.
5. Pour in the vegetable stock or water and bring the soup to a simmer. Cook until the vegetables are fully tender, about 30 minutes. Stir in the reserved celery leaves.
6. Purée the soup in batches, transferring the vegetables and broth to a blender and never filling the pitcher more than halfway. Begin blending on low, then slowly raise the speed to high and blend until completely smooth. If the texture needs it, pass the soup through a fine-mesh strainer, then return it to the pot.
7. To serve, bring the soup back to a simmer and stir in the cream. Season with salt and a few tablespoons of the grape-pickling liquid. Serve hot, topped with the peanut crumble and pickled grapes.