2 pounds Yukon Gold potatoes, cut into 1-inch pieces
1/3 cup olive oil
4 garlic cloves (3 thinly sliced and 1 minced)
1/3 cup grated Parmigiano-Reggiano
1/4 cup well-stirred tahini
2 tablespoons water
3 tablespoons fresh lemon juice
1 pkg Save the Season kale leaves
Accompaniment: lemon wedges
Preheat oven to 450°F with rack in upper third.
Toss potatoes with oil and 1/2 teaspoon each of salt and pepper in a large 4-sided sheet pan, then spread evenly. Roast, stirring once, 10 minutes.
Stir in sliced garlic and roast 10 minutes more.
Sprinkle with cheese and roast until cheese is melted and golden in spots, about 5 minutes.
Meanwhile, purée tahini, water, lemon juice, minced garlic, and 1/2 teaspoon salt in a blender until smooth, about 1 minute. (Add a bit of water if sauce is too thick.)
Toss kale with hot potatoes and any garlic and oil remaining in pan, then toss with tahini sauce and salt and pepper to taste.