1.Preheat oven to 220°C (200°C fan-forced). Line baking trays with baking paper. Halve pastry sheets so you have 4 rectangles.
2.Assemble tarts. Lay 2 pastry pieces on each baking tray and place onion slices, artichokes, ricotta and thyme over pastry, leaving 1cm border around edge. Drizzle oil over topping and season with salt and pepper.
3.Cook tart. Bake for about 25 minutes or until pastry is cooked and ricotta is golden, swapping trays around after 15 minutes.
4.Remove tarts from oven and top with basil leaves. Serve hot or at room temperature with a simple green salad, if desired.
We used marinated artichoke hearts, preserved in a seasoned oil, to add extra flavour to the tarts.