Whisk the eggs with the salt. Add the milk or water, flour, and olive oil. Whisk just until smooth, then let the batter rest for 15 minutes.
Trim the base from each blossom. Open it along one side and gently flatten the petals.
Preheat a crêpe pan or nonstick skillet, then reduce the heat to low. Pour in a small ladleful of batter and tilt the pan to spread it into a thin layer.
Immediately lay one opened blossom on the wet batter and gently press the petals flat with a spatula.
When the batter looks set and the underside is still pale, flip the crêpe. Cook briefly on the other side, then repeat with the remaining batter and blossoms.
Serve plain or fill with ham and cheese or zucchini and ricotta. Warm filled crêpes over low heat for about 1 minute on each side.