- 1 small shallot, finely chopped
- 2 tablespoons fresh lemon juice
- 1 large egg yolk
- 1 garlic clove, finely grated
- 1/4 teaspoon kosher salt, plus more
- Pinch of cayenne pepper
- 1/2 cup vegetable oil
- 2 tablespoons buttermilk
- 2 tablespoons crème fraîche
- Freshly ground black pepper
- 1 1/2 pound sugar snap peas, untrimmed, divided
- 2 tablespoons olive oil, divided
- 1 tablespoon thinly sliced drained oil-packed Calabrian chiles
- Flaky sea salt (such as Maldon)
- Mix shallot and lemon juice in a small bowl. Whisk egg yolk, garlic, kosher salt, cayenne, and 2 teaspoons water in a medium bowl. Whisking constantly, gradually drizzle in vegetable oil, drop by drop at first, until aioli is thickened and smooth. Gently mix in buttermilk, crème fraîche, and shallot mixture; season with kosher salt and black pepper.
- Prepare grill for medium-high heat.
- Toss half of snap peas with 1 tablespoon olive oil in a medium bowl; season with kosher salt and black pepper. Set a wire rack or grill basket on grill grate and grill peas on rack, turning occasionally, until lightly charred, about 4 minutes; return to bowl.
- Cut raw peas in half crosswise on a diagonal and toss with grilled peas along with remaining 1 tablespoon olive oil; season with black pepper. Spoon some aioli on a platter and top with snap peas, chiles, and sea salt. (Reserve remaining buttermilk aioli for another salad, or use it as a dip.)
- Do ahead: Buttermilk aioli can be made 3 days ahead. Cover and chill.