Preparation time: 30 minutes
Cooking time: 30 minutes

1. Melt 15 g of butter in a small saucepan. Slice the 100 g red onion very thinly and add to the butter. Season with salt and pepper. Cook over low heat for 20 to 30 minutes until a deep blond color. Add the vinegar. Reduce by half, then add the water and reduce by a quarter.
2. Cut the 40 g of beets into small pieces and add to the onion mixture. Return to the boil and cook for a minute or two longer. Put everything into a blender and blend to a smooth sauce; strain. Return to the boil, and whisk in the remaining 60 g of butter and 25 g of finely diced beet.
3. Cut the 150 g of onion into 1 cm cubes, separating the layers. Place in a medium saucepan with the 20 g butter, salt and pepper. Cook gently, covered. When almost cooked, cut up the zest of an untreated lemon very finely and add to the pan.
4. Cut the melon into 2 cm (4/5") thick slices, remove the peel, and cut into 2 mm thick triangles. Add the melon to the pan. Season with salt and pepper, add a drizzle of lemon juice and correct the seasoning. Add the remaining 25 g of diced beet.
5. Season the liver with salt and pepper and cook in butter in a skillet until still slightly pink.
6. Arrange some of the onion and melon garnish on each plate and add a slice of calf's liver. Add a squeeze of lemon juice and spoon on some of the sauce. Sprinkle with cooked butterfly pasta and garnish with a spear of chive. Serve immediately.