2 tablespoons olive oil
1 onion - peel and finely chop
3 tablespoons plain flour T55
200 ml dry white wine
400 ml beef broth
4 tablespoons estragon - finely chop
30 ml lemon juice - freshly squeezed
200 ml heavy cream 36%
salt - to your taste
black pepper - freshly ground from a pepper mill, to your taste
