Make the reduction by combining the vinegar, shallots, sugar, tarragon, and peppercorns in a saucepan. Bring to a gentle simmer and reduce by about half. Strain and set aside.

For the beurre blanc base, bring the water, cream, honey, and salt to a simmer. Blend the reduction and slowly add the cornstarch slurry, then return everything to the pot and simmer gently until smooth and slightly thickened.

Using an immersion blender, slowly blend in the cold butter a few cubes at a time until fully emulsified. Blend in the lemon juice, truffle oil, and truffle paste. Set aside and keep warm.

Make the béchamel by melting butter in a saucepan and sweating the onion until soft. Stir in the flour and cook briefly. Slowly whisk in the milk, cream, and salt until thickened. Let cool completely.

Combine all the ravioli filling ingredients in a bowl or food processor and blend until very smooth. Transfer to a piping bag and chill until ready to use.

Make the pasta dough by combining the flour, egg yolks, whole egg, and olive oil. Knead until smooth and elastic, then wrap and rest for 30 minutes.

Roll the pasta thin, pipe the filling, seal, and cut into ravioli. Keep covered so they don’t dry out.

Cook the ravioli in well-salted boiling water for 2–3 minutes, gently stirring at the beginning to prevent sticking.

While the ravioli cook, melt butter in a pan and sauté the prawns until just cooked through. Add the pasta water and let it reduce slightly.

Add the drained ravioli and black truffle butter sauce to the pan. Toss gently for about 30 seconds until everything is glossy and coated.

Plate the ravioli and prawns, finish with crispy onions, freshly shaved Grana Padano, a drizzle of olive oil, and herbs. Serve immediately.