Tempura Green Beans with Mushroom Salt and Shallot Dip

Ingredients

• 2 shallots, 1 coarsely chopped, 1 thinly sliced into rings
• 4 scallions, white and pale-green parts only, thinly sliced
• 1 tablespoon Champagne vinegar or white wine vinegar
• Kosher salt
• ¼ cup mayonnaise
• ¼ cup sour cream
• 2 tablespoons buttermilk
• 2 tablespoons finely chopped fresh chives
• Freshly ground black pepper
• ¼ cup vegetable oil
• 3 tablespoons porcini powder, divided
• 1 tablespoon kosher salt
• Vegetable oil (for frying; about 6 cups)
• ½ cup all-purpose flour
• ½ cup cornstarch
• ½ teaspoon baking powder
• ¼ teaspoon kosher salt
• 1 cup chilled club soda
• 8 ounces green beans, trimmed
• A deep-fry thermometer

Steps

1. Place chopped shallot, scallions, and vinegar in a food processor and season with salt. Process until finely chopped; transfer to a medium bowl. Whisk in mayonnaise, sour cream, buttermilk, and chives; season dip with salt and pepper.
2. Cook oil and shallot rings in a medium skillet over medium heat, stirring occasionally, until shallots are golden brown, about 4 minutes. Using a slotted spoon, transfer shallots to paper towels to drain; season with salt. Set aside for serving.
3. DO AHEAD: Dip (without crispy shallots) can be made 1 day ahead. Cover and chill.
4. Mix salt and 1 Tbsp. porcini powder in a small bowl; set mushroom salt aside.
5. Fit a large pot with thermometer; pour in oil to measure 2". Heat over medium-high until thermometer registers 375°.
6. Meanwhile, whisk cornstarch, flour, cornstarch, baking powder, kosher salt, and remaining 2 Tbsp. mushroom powder in a small bowl. Add club soda; whisk until batter is smooth.
7. Working in batches, dip green beans in batter, letting excess drip back into bowl, and fry, stirring gently with a slotted spoon if green beans stick together, until golden, about 3 minutes per batch. Using a spider or slotted spoon, transfer to paper towels to drain. Sprinkle with mushroom salt.
8. Top dip with crispy shallots and serve alongside green beans.