Sole Glorias

Peel the prawns and reserve heads and shells. In a saucepan with 100 ml of water, bring the heads and shells to boil. Grate the onion and sauté in a pan with a tablespoon of olive oil. Preheat oven to 200 ºC. Roll up the sole fillets with shrimp inside and close with a toothpick. Place the rolls of sole in a baking tray. Once the onion is sautéed, add the 200 ml of sparkling wine and the water used to cook the prawn heads and shells; also add 1 sprig of cilantro and reduce. Once reduced, purée in blender for the sauce. Put the rolls of sole in the oven and bake for 5 minutes at a temperature of 180 °C. Take them out and plate 4 rolls, top with the sauce and garnish.