This is a zippy, hearty salad that will forever open your mind to celery's deliciousness and versatility. Make it for a simple weeknight dinner, tote it to a picnic or potluck, or serve it at your next soirée. Once assembled, it can easily hang out at room temperature for a few hours—just give it a another toss before digging in. And while I like its contrasting textures best on day one, it’s also good the next day, after the lentils have soaked up the spunky vinaigrette and the celery has relaxed its crunch. It’s like getting two very good salads for the price of one.
Place lentils and bay leaf in a saucepan and cover by several inches of water. Bring to a boil, then turn down the heat and simmer until the lentils are tender but still firm, about 20 minutes (or according to package directions). Add additional water, if needed, to keep the lentils covered.
Meanwhile, to make the vinaigrette: Mince and smash the anchovies into a paste with the side of your knife. In a small bowl or jar with a tight fitting lid, combine the anchovies, shallots, capers, lemon zest and juice, and a few pinches of salt. Let macerate for about 5 minutes, then add the olive oil, whisking (or shaking) to emulsify. Taste and adjust the acid and seasoning.
When lentils are done, drain well in a colander, discarding the bay leaf. Return the lentils to the pan. Immediately fold in 2 to 3 tablespoons of the vinaigrette and the raisins. Let cool for about 5 to 10 minutes, then taste and adjust seasoning.
In a serving bowl, toss the celery and celery leaves (and/or the parsley and arugula) with 1 tablespoon of the vinaigrette and a pinch of salt and red pepper flakes, then add the lentils, almonds, and pecorino. Taste again, adding more vinaigrette, lemon juice, or salt, as needed. Serve immediately or at room temperature.