Preheat the oven to 180°C. Grease a tart dish with some coconut oil.
Add the base ingredients to a food processor and blitz until combined. Press into the tart tin to form a base.
In a medium-sized pot over medium heat, combine the sugar, Maizena, salt, water and lemon juice. Cook until it just starts to bubble.
While the sugar mixture is heating up, in a small bowl combine the egg yolks and lemon zest. Whisk to combine.
As soon as the sugar mixture just starts to bubble and turns translucent, temper the egg yolks by slowly pouring in a ladleful of the hot sugar mixture while whisking the egg yolks. Once combined, add all the egg yolks to the sugar mixture. Cook until it just starts to bubble.
Once it bubbles, turn off the heat and add in the coconut oil. Whisk until it melts. Set aside.
After the lemon curd is off the heat, make the meringue. Pour the egg whites into a bowl attached to a stand mixer and whisk until bubbly, then add the vanilla and lemon juice. Continue mixing and once the egg whites are fluffy, add the sugar one tablespoon at a time until stiff and glossy.
Pour the curd into the crust, top with the meringue and bake for 25 to 30 minutes, until the meringue is lightly golden.