Mix oat flour and almond flour to make tart dough.
Add olive oil and unsweetened almond milk, and knead again.
Spread the dough thinly into a finger-shaped mold.
Bake in a preheated oven at 180°C for 10 minutes.
Let the baked dough cool.
Mix Greek yogurt, lemon juice, lemon zest, and stevia to make the filling.
Place the filling on top of the cooled tart base.
Garnish with lemon slices or mint.