How to Make It
Spoon the yogurt into a strainer lined with a paper coffee filter or cheesecloth. Set the strainer over a small bowl and refrigerate until most of the liquid has drained off the yogurt, about 3 hours.
In a mini-processor or blender, combine the 1/3 cup basil leaves, blanched garlic puree and drained yogurt and season with salt and pepper. Puree the sauce until smooth. Transfer to a bowl.
In a steamer basket set over a pan of simmering water, cook the potatoes until tender, about 17 minutes. Let cool slightly; cut into quarters.
Meanwhile, in a spice grinder or mortar, grind the dried porcini, fennel seeds and peppercorns to a fine powder. Transfer the powder to a plate. Pat the tuna steaks dry and season on both sides with salt. Sprinkle the porcini powder all over the tuna, pressing it into the surface.
Lightly coat a large nonstick skillet with vegetable spray and heat. Add the tuna steaks and cook over high heat until browned on the bottom, 2 to 3 minutes. Lightly coat the top of the tuna with vegetable spray, then turn and cook until browned outside but still rare in the center, about 3 minutes longer. Transfer the tuna to a cutting board and cut into 1/2-inch-thick slices.
Wipe out the skillet and set it over high heat. Add the spinach, season with salt and pepper and cook, stirring occasionally, just until wilted. Add the tomatoes and stir gently until heated through. Mound the spinach and tomatoes in the center of 6 plates. Arrange the tuna slices and potatoes around the spinach and drizzle each serving with about 2 tablespoons of the basil sauce. Garnish with the chopped basil and serve at once.
Blanched garlic may be used in place of roasted garlic in almost any dressing or condiment. And blanching has one significant advantage over roasting: it requires no oil. For on-half cup of blanched garlic puree, peel the cloves from two large heads of garlic. Put the cloves in a pan, add water to cover and bring to a boil over high heat. Drain the garlic and return it to the pan. Repeat the process three more times until softened. Transfer to a bowl and mash with a fork until smooth.
One Serving Calories 357 kcal, Protein 41 gm, Carbohydrate 31 gm, Cholesterol 54 mg, Total Fat 8 gm, Saturated Fat 2 gm.