Preheat oven to 350 degrees Fahrenheit.
Add the oat flour, tapioca flour, coconut oil and sea salt to a food processer and pulse until a crumbly mixture is formed. Then add the maple syrup and ice-cold water and pulse again until the dough starts to form.
Press the dough into a ball and roll out between two non-stick surfaces, such as a silicone baking mat and some parchment paper.
Add the dough to your tart pan and bake for 15 minutes.
Meanwhile, add the egg whites to a mixing bowl and mix until they become frothy. Then add the lemon juice and keep whisking until soft peaks form. Finally, add the sugar slowly while whisking, and whisk until medium/soft peaks form.
Once your tart has baked, add your lemon curd and then top with meringue. Bake at 425 degrees Fahrenheit for 10-15 minutes, until top is lightly browned.
Add some fresh lemon zest and enjoy!