This is a very simple sauce that I use a lot. The recipe is in cups but I have used a mug and as long as you make the sauce using the same measuring item you should be ok.
Simple Lemon Sauce.
1 cup of white wine
1 cup of water
1 chicken stock cube
1/2 cup of fresh lemon juice ( no fresh lemon? jif or equivalent will be fine)
3/4 cup of brown granulated sugar
1 lemon zest (can be optional, but it looks good too)
Bring to the boil to dissolve the sugar
then you will need 1/4 cup of cornflour mixed with 1/4 cup of water and add to the boiled mixture, for the consistency you like. serve immediately.