Creamy Leek and Mushroom Pasta

Name: Creamy Leek and Mushroom Pasta
Ingredients: 1.1 lb (500g) dried wholemeal pasta of your choice; 1 tbsp olive oil; 1 tbsp butter; 2 large leeks, thoroughly washed and thinly sliced; 1.1 lb (500g) mushrooms (whichever kind you like); 1 cup canned artichoke hearts, roughly chopped (optional); 1½ cups vegetable stock or white wine, or a combination; ½ cup water; A pinch of saffron (optional); 1tbsp plain flour; ⅓ cup cream; 2 tbsp cream cheese; 2 good handfuls of baby spinach; Zest of half a lemon; 2 tbsp shelled pistachios or walnuts, roughly chopped; A handful of roughly chopped parsley to serve; Shaved parmesan cheese to serve