Preheat your oven to 180°C (350°F) and line your tart pan with the chilled pie crust, pressing into the edges. Prick the bottom lightly with a fork, then chill in the fridge for 10 minutes.
Blind-bake the crust: line with parchment paper, fill with pie weights or dried beans, and bake for 10 minutes. Remove the weights and parchment, then bake for another 5 minutes until just golden and crisp.
Meanwhile, trim the woody ends off the asparagus and blanch the spears in boiling salted water for 2-3 minutes until bright green and tender. Immediately transfer to ice water to stop the cooking and preserve color.
Drain the spinach thoroughly, then sauté in a skillet with a tablespoon of olive oil or butter until wilted, about 1-2 minutes. Transfer to a towel, squeeze out excess moisture, and roughly chop.
In a large bowl, whisk the eggs until smooth and slightly frothy. Add the heavy cream, chopped herbs, and season with salt and pepper. Whisk again until well combined.
Spread the drained spinach evenly over the bottom of the cooled crust, then arrange the blanched asparagus spears on top in a fanned pattern. Sprinkle the grated cheese evenly over the vegetables.
Pour the custard mixture over the fillings, allowing it to settle into all the nooks. Gently tap the tart pan on the counter to release any air bubbles and level the surface.
Bake the quiche in the oven for 35-40 minutes, until the edges are golden and the center is just set with a slight wobble. The custard should be firm but still tender.
Remove the quiche from the oven and let it rest for at least 10 minutes. This allows the custard to firm up, making it easier to slice cleanly.
Slice the quiche with a sharp knife, serving warm or at room temperature. Garnish with extra herbs if desired and enjoy the bright, creamy flavors in each bite.
