• Bring 5 cups of water to a boil. Add the barley and salt; reduce the heat and cook, uncovered, until the barley is tender, about 30 minutes. Drain. Meanwhile, cook the kale in boiling salted water until it is tender, 6 to 10 minutes. Drain, saving 1/4 cup of the cooking water. In a food processor, puree the drained kale with the water until smooth.
• Preheat the oven to 375 degrees. Coat six individual molds lightly with oil.
• Heat the olive oil in a skillet on medium-high flame. Add the mushrooms and cook, stirring occasionally, until the mushrooms are golden brown and there is no liquid left in the skillet, about 10 minutes. Remove six browned mushroom slices from the pan and place one slice in the bottom of each cup.
• Over medium flame, stir the flour into the browned mushrooms, and cook a few minutes to make a roux. Slowly add the vegetable broth, whisking until the liquid thickens a bit. Stir in the garlic, lemon zest and parsley.
• Mix the barley, pureed kale and the cheese into the mushroom sauce. Season to taste with salt and pepper. Divide the mixture into the cups. (see note) Bake about 30 minutes, or until the edges are just browned.

While the barley cups bake, prepare the sauce:

• Whisk tahini with the hot water until smooth. Whisk in lemon juice, garlic, salt and cayenne. Taste, and add more seasoning if needed.

To serve:

• Out of the oven, let the ramekins cool 5 minutes. Then run a knife around the edges and invert onto plates. Serve with the sauce, garnished with parsley leaves or thin lemon slices.