Labneh
1 quart organic Greek yogurt (or another plain whole-milk strained yogurt
1 tablespoon finely grated lemon zest plus 3 tablespoons fresh juice (from 2 lemons)
¾ teaspoon kosher salt
Lemon Vinaigrette
¼ cup finely chopped shallot (from 1 medium [1 1/2 ounce] shallot)
¼ cup fresh lemon juice (from 2 lemons)
1 tablespoon Champagne vinegar or white wine vinegar
1 teaspoon kosher salt
½ teaspoon black pepper
½ cup extra-virgin olive oil
Toasts
8 (1/2-inch-thick) baguette slices or 4 rustic white bread slices, halved crosswise
Extra-virgin olive oil, for brushing bread
Salad
Kosher salt, to taste
⅔ cup shelled English peas (from about 8 ounces unshelled pea pods)
3 ounces medium-size fresh asparagus spears (about 8 spears total), tough stems snapped off and discarded
3 ounces (about 1 cup) fresh sugar snap peas, strings removed
6 (3 ounces total) breakfast radishes
3 (2 2/3 ounces each) heads Little Gem lettuce or romaine lettuce hearts, leaves left whole and removed from core (about 10 cups)
1 tablespoon fresh lemon juice (from 1 lemon)
2 tablespoons finely chopped fresh chervil (or 1 tablespoon each finely chopped fresh flat-leaf parsley and tarragon), plus leaves for garnish
2 tablespoons finely chopped fresh dill, plus leaves for garnish
2 tablespoons finely chopped fresh tarragon, plus leaves for garnish
2 tablespoons finely chopped fresh flat-leaf parsley, plus leaves for garnish
15 to 20 (1-inch-long) pieces fresh chives (from about 3 chives)
Additional Ingredients
Finishing-quality extra-virgin olive oil
Sweet smoked paprika (optional)
Place yogurt, lemon zest and juice, and salt in a medium bowl; stir using a rubber spatula to combine. Line a second medium bowl with a double layer of cheesecloth long enough to hang 2 inches over edge of bowl. Add yogurt mixture to bowl. Tie edges of cheesecloth together with kitchen twine, forming a loose bundle. Thread handle of a long wooden spoon or a long, heavy-duty skewer through cheesecloth just below knot, pushing through until bundle hangs from center of handle. Place in a tall container, resting handle across top edges with pouch hanging down center. There needs to be least 2 inches of space between bottom of pouch and bottom of container.
Refrigerate yogurt, uncovered, for 3 days to allow whey to drain from yogurt. Unwrap cheesecloth; transfer Labneh to an airtight container, and discard cheesecloth. Labneh can be refrigerated up to 3 days. Bring to room temperature before using.
Stir together shallot, lemon juice, vinegar, salt, and pepper in a medium bowl; let stand 10 minutes. In a slow, steady stream, gradually whisk in oil, whisking constantly to emulsify. Vinaigrette may be stored in an airtight container in refrigerator up to 2 days. Bring Vinaigrette to room temperature, then whisk before using.
Preheat oven to 350°F, or preheat a sandwich press until smoking hot. If using an oven, arrange bread slices in a single layer on a rimmed baking sheet. Brush tops with oil . Bake in preheated oven until golden brown and crispy, 15 to 20 minutes, rotating baking sheet from front to back halfway through bake time. (If using a sandwich press, brush bread slice tops with oil, and toast until golden brown, about 2 minutes.) Transfer Toasts to a work surface, and let cool to room temperature, about 5 minutes.
Bring a large saucepan of water to a boil over high. Fill a medium bowl with ice water. Place a layer of paper towels in a small bowl. Generously salt boiling water. Place English peas in a fine mesh strainer. Place strainer with peas into boiling water; cook until peas are tender-crisp, about 2 minutes. Lift strainer from water, and plunge into ice bath. Keep peas in ice water until cold, about 1 minute. Lift strainer from ice water, and pour peas into bowl with paper towels to drain. Set aside.
Starting at the tip of 1 asparagus spear and keeping entire tip intact, cut asparagus on a very sharp angle into 1/8-inch-thick slices; transfer slices to a medium bowl. Slice snap peas on a very sharp angle into 1/8-inch-thick slices; add to asparagus in bowl. Thinly slice radishes on a mandoline into about 1/16-inch pieces. Add radish slices and drained peas to snap peas and asparagus in bowl. Add 3 tablespoons Lemon Vinaigrette; toss until evenly combined; set aside to marinate while preparing remaining Salad ingredients.
Place lettuce leaves in a large bowl. Sprinkle with lemon juice and salt to taste; toss to coat. Drizzle with Lemon Vinaigrette to taste. Sprinkle one-fourth (about 2 tablespoons total herbs) of the chervil, dill, tarragon, and parsley over lettuce, and toss gently with your hands to incorporate. Repeat adding herbs in 3 more additions, mixing with your hands to coat lettuce and evenly distribute herbs between each addition.
Slather 1 heaping tablespoon Labneh on each Toast, leaving edges visible. (This is purely for aesthetic reasons, but for me, that's as good a reason as any.) Transfer to a platter. (Reserve remaining Labneh for another use.) Drizzle Toasts with finishing-quality olive oil, and sprinkle each Toast with a pinch of paprika, if using.
Transfer lettuce mixture to a large platter, with leaves slightly overlapping one another. Spread marinated asparagus mixture over lettuce. Sprinkle with chives, and garnish with chervil leaves, dill leaves, tarragon leaves, and parsley leaves. Serve with Labneh Toasts.