Gnocchi Leek Soup With Greens

Name: Gnocchi-Leek Soup With Greens
Ingredients: ⅓ cup vegetable oil; 2 large leeks, white and pale green parts only, thinly sliced, divided; Kosher salt; 1 lemon, halved, seeds removed; 2 Tbsp. unsalted butter; 1 Parmesan rind (optional), plus shaved Parmesan for serving; 6 cups low-sodium vegetable broth; Freshly ground pepper; 1 1.1-lb. package shelf-stable or refrigerated gnocchi; 2 (packed) cups torn Tuscan kale leaves; Torn dill sprigs (for serving)