For making the Ravioli dough, make a hole in the heap of multigrain flour. Add the three eggs and mix the flour and the eggs together. Add the water and knead the dough for 10 min, or until smooth to touch. Cover it with a cling film and refrigerate for 30 min.
For the filling, heat oil and add the onions and the salt. When these become translucent, add the ham. Cook on high heat for roughly 3 min. Now add the rest of the ingredients for the filling and cook for 2 min on medium heat. Switch off the gas. After the mixture cools down a bit, blitz it in the food processor (not very finely), after decanting off the liquid, if any.
Divide the Ravioli dough into two parts. Out of each dough, roll out a big, thin rectangle on a lightly floured surface. Cut long strips of 2-inch width. Brush one strip with egg-white wash. Put 1 teaspoonful of the filling on the strip, leaving a gap of 1 inch between two adjacent fillings. Overlap the other strip over this strip and seal the two strips together, making sure that there are no air bubbles trapped. Using a Pizza cutter or a Pastry wheel, cut out 2-inch squares in such a way that the filling comes in the centre of each ravioli.
Alternately, cut out 2-inch squares out of rolled-out thin Ravioli sheets or “rotis”. Add 1 tsp filling in the centre. Brush the edges of each of the squares with egg wash and overlap each with another square in such a way that the filling is at the centre. Press slightly to seal properly.
Half-fill a shallow pan with water. Add 1 tsp salt and let it come to a rolling boil. Now simmer the flame and carefully add the raviolis, not too many at a time. After 2 min, the raviolis get cooked and float on the surface.
Remove the raviolis with a slotted spoon. Season with pepper.
Immediately, in another pan, heat butter with chopped sage leaves until the butter becomes golden brown. Remove from heat and sprinkle the Burnt Butter Sauce over the Multigrain raviolis. Garnish with Parmesan.