This is delicious and it makes quite a lot so if you stop at step 1 it makes a great dessert served in stemmed glassware with cream or ice-cream - although I did make this to top Classic Pavlova #174892.
Hull and halve strawberries, leaving about 8 whole for pavlova decoration, and put into a medium bowl; scoop passionfuit into bowl; add Cointreau to taste & sugar and chill for an hour or two.
Before topping pavlova with strawberries and passionfruit, drain juice from the fruit, being careful not to lose any of the passionfruit pulp; taste and add more Cointreau and sugar if necessary.
Thicken the juice with arrowroot over a low heat to make a pouring sauce, not too thick as it will thicken as it chills - amount of arrowroot needed depends on how much juice you have from the strawberries.
After adding cream to pavlova, top with the strawberries, both sliced and whole (leave leaves on whole strawberries) and pour over the sauce.