Preheat the oven to 350°F (180°C). Lightly grease the wells of a mini muffin pan.

Roll out the pie dough. Roll out to achieve a slightly larger circle. Use a cookie cutter or a cup to cut out 12 3-inch circles. Press the dough into the muffin molds. You can press them smooth or keep them slightly ruffled.

Bake for 10 minutes, then remove from the oven and let cool.

In a bowl, whisk together the eggs, cream, and Gruyère cheese with a pinch of salt. Finely slice 2 asparagus spears and stir them into the mixture. Cover and set aside to infuse.

Once cooled, pour the cream mixture into each of the crusts. Bake for 14 minutes or until just set. Let cool for a few minutes before removing from the pan.

While the tarts bake, whisk together the olive oil, vinegar, mustard, and a pinch of salt.

Shave the remaining spears of asparagus with a potato peeler. Dress them with the vinaigrette.

Top each tartlet with asparagus ribbons and finely shredded Gruyere cheese. These can be served hot or cold.