I saw Nigella make a cocktail on one of her TV shows, I made it and it was amazing for a party. I know that it contains gin and sour apple liqueur, but there was another ingredient that I have forgotten and I have mislaid the recipe. Please help!
We suspect that the recipe you are looking for is the Green Apple Martini (also called "Kryptonite" by Nigella) and it appears on p197 of Nigella Express. The cocktail contains gin or vodka (as you prefer) mixed with sour apple liqueur and Monin Green Apple syrup. The Monin syrup may be available in some liquor stores/off-licenses and is available on-line.
To match the green theme we would suggest an accompaniment of Quick Crostini with Avocado and Green Pea Hummus, also in Nigella Express on p201. Otherwise the Martini Olives (from the same book, p319) or the spiced Bar Nuts featured in Nigella Bites and also on Nigella's website.