- To make the crust: Whisk together the flour and salt. Work in the cream cheese and butter until the mixture is crumbly.
- Drizzle in 4 tablespoons of the water, tossing to moisten evenly. Add the remaining water if needed to make a cohesive dough. Pat the dough into a disk 3/4" thick, wrap, and refrigerate for 30 minutes.
- To make the filling: Preheat the oven to 425°F. Snap the woody stems from the bottoms of the asparagus stalks and toss the spears in the olive oil to coat. Arrange in a single layer on a parchment-lined baking sheet, and roast for 10 to 15 minutes, until lightly browned. Remove from the oven and cool to room temperature. Once cool, cut the asparagus into 1 1/2" pieces; a pair of scissors works well here.
- In a medium bowl, mix together the ricotta, egg, half of the Parmesan, chives, and lemon zest.
- To assemble: On a lightly floured surface, roll the dough into a 14" circle. Transfer it to a parchment-lined baking sheet.
- Spread the ricotta mixture evenly over the dough, leaving a 2"-wide strip uncovered around the outside edge. Arrange the asparagus pieces over the filling.
- Fold the bare edges of the dough toward the center, pleating as needed. Brush the exposed dough with the egg wash, and sprinkle the remaining Parmesan over the entire galette.
- Bake the galette in a preheated 425°F oven for 25 to 30 minutes, until the crust is golden brown and the filling is bubbly. Remove it from the oven and allow it to cool for 10 minutes before serving warm; or cool and serve at room temperature.
- Store, covered and refrigerated, for up to 1 week.