Let the dough sheets rest at room temperature for about 15-20 minutes. Clean, wash and roughly grate the zucchini. Mix with 1/2 teaspoon salt and let steep for about 10 minutes. Melt the butter in a saucepan.
Crumble the feta cheese. Wash the parsley and shake dry. Pluck the leaves and chop finely. Wash the organic lemon with hot water, rub dry and rub off about 1 teaspoon of the zest. Whisk the eggs with the cream. Squeeze the zucchini well, stir into the egg mixture with the feta cheese, finely chopped parsley and lemon zest. Season with salt and pepper.
Preheat the oven to 180 degrees (convection: 160 degrees). Grease a tart pan with a lifting base (approx. 11 x 35 cm) with a little liquid butter. Unroll the pastry sheets and cut in half. Overlap the shape, also on the edge, with the strips of dough, brushing each flat sheet thinly with melted butter. Add the egg and zucchini mixture and bake in the preheated oven for about 30 minutes. Spread the olives on the tart about 10 minutes before the end of the baking time. Garnish with mint leaves and serve.