Slowly add the prosecco or champagne, stirring well.
Place back on a low heat and stirring constantly, simmer for 3 minutes. Add the cream or yogurt and bring to the boil. Boil for 2 minutes. Add the dill and stir well.
Season to taste and simmer for 4 minutes.
If using, add the capers.
Notes
I chose to serve it on a dish of stir-fried broccoli with udon noodles. The sauce can be portioned and frozen.