|  | 4 oz (125 g) cold butter cut into cubes | 
                      
                      
                      
                        
                          |  | 2 – 3 tablespoons cold water | 
                      
                      
                      
                        
                          |  | 3 – 4 white potatoes, peeled and cut into very thin slices | 
                      
                      
                      
                        
                          |  | 2 medium size leeks, white and light green part, sliced thinly | 
                      
                      
                      
                        
                          |  | 1 lb (½ k) spinach leaves, without stems | 
                      
                      
                      
                        
                          |  | 1 cup cheddar cheese or similar, shredded |