In a food processor, combine the cashews with the nutritional yeast and water and process to a fine paste. Transfer the paste to a bowl, stir in the olives and season with salt and pepper.
Light a grill. Brush the eggplant slices (there should be about 24) with olive oil and grill over moderately high heat, turning once, until tender and lightly charred, 2 to 3 minutes. Arrange the eggplant on a work surface and season with salt and pepper. Spoon 1 tablespoon of the cashew filling onto one end of each eggplant slice. Roll into tight cylinders. Cover with plastic wrap.
Brush all of the vegetables with olive oil and season with salt and pepper. Grill the vegetables in batches until tender and lightly charred, about 3 minutes for the tomatoes and 6 minutes for the onions, peppers, eggplant and zucchini. Transfer the grilled tomatoes to a blender and puree until smooth.
Peel, seed and dice the peppers and chop the onions. Add them to a large deep skillet along with the 2 tablespoons of oil and the garlic, bay leaf, thyme and oregano. Cook over moderately high heat until tender, 5 minutes. Add the wine and boil until evaporated, 2 minutes. Add the tomato puree and water, season with salt and pepper and simmer until the sauce is slightly reduced, 15 minutes. Cut the eggplant and zucchini into 1/2-inch pieces; add to the skillet. Simmer 10 minutes longer. Discard the bay leaf and stir in the basil.
Spoon the ratatouille into shallow bowls and top with the involtini. Spoon a dollop of harissa on top and serve right away.