For the dough:
Mix all the ingredients and knead until every ingredient is thoroughly integrated. Wrap the dough in plastic wrap and leave in the fridge for 1 hour.
After that, butter the baking pan and roll out the dough over it using a rolling pin, the cover the pan with the dough. Dock the dough with a fork and put in the preheated oven for 20 minutes or until the dough edges are golden.
For the filling:
Dissolve the cornstarch in half a cup of almond milk and set aside. Heat the remaining almond milk in a pot, along with the lemon zest and cinnamon stick. When it starts boiling, remove the cinnamon and lemon zest, and add the sugar and dissolved cornstarch. Cook over medium-low heat for 10 minutes or until it thickens and reduces to half its volume, stirring constantly.Then the custard is ready, let it cool down until warm, then cover with a lid and allow to cool down completely.Fill the pie with the cool custard and put the sliced strawberries over the whole surface of the pie. Decorate with mint leaves as you desire.