*This recipe requires a countertop blender or an immersion blender.*
To make the ravioli:
1. Trim root ends and cut each beetroot in half. Starting in the middle section, cut a total of 24 wafer-thin slices of approximately the same size. (The rest of the beetroots can be used for another dish such as a soup or salad).
2. Spread the slices on a large baking tray. Salt lightly and set aside. The salt will draw out the moisture, and the slices will be more flexible.
3. Mince the parsley, starting with the stems. The parsley stems will go into the ravioli filling, and the leaves will go into the sauce.
To make the tofu, walnut and mushroom filling:
4. Dice the tofu, quarter the mushrooms and finely chop the walnuts. Finely dice the dates.
5. Toast walnuts in a dry pan and set aside. Fry mushrooms in a little oil until golden brown. Add the parsley stems, tofu and diced dates and continue frying.
6. After approx. 10 min., put the mixture in a high-sided bowl together with the walnuts, mustard, tomato paste, soy sauce and a pinch of salt. Purée with an immersion blender. Season to taste.
7. Blend the finely minced parsley leaves with oil and lemon juice to create a fresh green sauce.
8. Rinse the beetroot slices (or they will be too salty) and pat dry with a clean kitchen towel. Arrange three beetroot slices on each of four plates. Top each slice with a walnut-size portion of the filling and cover with a second slice. Gently press down the edges to seal.
Drizzle with parsley sauce, sprinkle with a few flakes of fleur de sel, and season with freshly ground pepper.