Lightly spray 6 x 10cm-diameter fluted tart tins with oil.
Cut six circles from the pastry and place the circles in the greased tins. Press to fit and trim off the excess. Place in the refrigerator for 15 minutes.
Remove from the fridge and place the tins on a large baking tray. Steam the asparagus for 2-3 minutes until tender, then drain and refresh under cold water (to retain colour).
Divide the asparagus between each pastry base and top with tomatoes, cut side up. Whisk the eggs, ricotta, parmesan, lemon zest and chives in a large bowl, season with salt and pepper and pour over the asparagus and tomato.
Bake for 25 minutes or until the pastry is golden and the filling is set. Serve with rocket leaves.