Preheat your oven to 180C (350F). Lightly grease a 23-cm (9-in) loose – bottom tart tin, or five smaller ones (10cm/4in diameter). Add the cookies to a food processor and blitz to a fine crumb. While blitzing, add the melted butter. Tip the biscuit mixture into your greased tart tin(s) and use a spoon to compress the mixture to form the biscuit base. Press the mixture up the sides of the tin(s) as well. Smooth out th e mixture making sure it’s an even layer all over.
Place the tin(s) in the oven to bake until firm for 12 minutes. Remove and allow to cool.
To make the lime filling, gently heat the coconut milk with the lime zest, juice and matcha (if using) in a medium-sized saucepan, over a low heat. Combine the almond milk, cornflour (cornstarch), and sugar in a bowl, and whisk until completely mixed. When the coconut milk is hot, pour the almond milk mixture into the pan and whisk over th e heat until the mix starts to thicken.
Continue to whisk for 2 more minutes or until the mixture is super-thick and custard-like. Carefully pour the lime filling mixture into the cooled pie case(s). Neatly spread the filling out using an of fset palette knife. Then place a layer of clingfilm (plastic wrap) directly over the filling, making sure there are no air pockets. This is important – it stops a skin forming.
Place the pie(s) in the fridge to chill for at least 4 hours before serving.
Prepare your meringue: Place all the ingredients into a mixing bowl, then using an electric whisk, whisk the ingredients until you have stiff peaks. This should take around 5 minutes. Pipe or spoon the meringue onto the pie(s) and finish with a blow torch or place under a hot grill (broiler) for a minute or so until browned. Add slices of lime and blackberries to serve.