- In a food processor, pulse the flour and salt until combined. Add the butter and pulse for several seconds until the butter is the size of peas. Add the milk. Pulse for several seconds more until the dough just begins to hold together, adding more milk if necessary. Remove the dough and shape into a disc.
- On a floured surface, roll the dough into a thin circle, about 28 cm (12 inches) across. Line a 25-cm (10-inch) quiche pan with the dough. Trim and flute or crimp the edges. Refrigerate for 30 minutes.
- With the rack in the lowest position, preheat the oven to 190°C (375°F).
- In a skillet over medium heat, soften the onion in the oil. Add the asparagus and sauté for 1 minute. Season with salt and pepper. Deglaze the skillet with the broth and reduce until nearly evaporated. Remove from the heat and let cool.
- In a bowl, combine the eggs and milk. Add the asparagus mixture and cheese. Adjust the seasoning. Pour the mixture into the pie shell. Arrange the asparagus tips on top. Bake until the centre of the quiche is barely set, about 45 minutes. Let rest for about 10 minutes before serving. Can be served hot, warm or cold.