Labneh is a strained yogurt that's so thick you can spread it. If you can't find it, use Greek yogurt. Or make your own labneh: Line a fine-mesh sieve with four layers of cheesecloth and place over a bowl deep enough to leave 2 inches between the bottom of the sieve and the bowl. Mix 1 1/2 cups whole-milk plain Greek yogurt with 1/4 tsp. salt and pour into the sieve. Refrigerate until very thick, 8 to 12 hours.