This is extra-deep, formed in a springform pan. The sides are more than 2 inches deep, so there is plenty of filling. The crunchy, buttery brown-sugar crumb on top is lightly accented with cardamom and lemon and is the perfect foil to the lush, rich, sour-cream-and-apple filling. When you slice a big wedge, it is picture-perfect; guests will think this came from a fancy bakery.

Note that there are several do-ahead steps for this dessert, particularly with the two chilling times for the crust.

Steps

1. Make the crust: Roll out half of the dough on a lightly floured surface to a 10-inch round. Use the bottom of a 9-by-3-inch round springform pan as a guide and cut out a 9-inch circle. Assemble the pan with the sides locked into place, and coat the inside with nonstick spray. Transfer the circle of crust to the bottom of the pan. Roll out the remaining dough and cut 2 long strips, each one 17 by 2 inches. Take one strip and fit it into the pan along the side; have the bottom slightly curve in over the bottom crust. Press the lower edge of the strip against the bottom crust to seal. Brush the short, vertical edges of the side strip with water and press the second strip into place, trimming to fit with about ½ inch of overlap. Press the overlapping edges well to seal. Refrigerate for at least 2 hours or overnight.
2. Position a rack in the middle of the oven. Preheat the oven to 400 degrees.
3. Cook the apples: Toss together the apple slices and sugar in a large sauté pan. Cook over medium heat, occasionally stirring gently, taking care not to crush the fruit pieces. Cook for about 5 minutes, just until the mixture begins to exude juices and the apples soften just a tiny bit. Remove from the heat, cool slightly, then sprinkle the flour over, and toss gently to coat.
4. Finish the filling: Whisk the eggs in a large bowl, then whisk in the sour cream, zest, and vanilla. Fold into the fruit mixture.
5. Assemble and prebake the pie: Remove the crust from the refrigerator and scrape the filling into the crust; it will come right up to the top of the crust. Bake for 15 minutes while you prepare the streusel.
6. Make the streusel: Combine all the streusel ingredients until well blended. After the pie has baked for 15 minutes, remove from the oven and turn the heat down to 375 degrees. Squeeze the streusel between your fingers and palms to create clumps ranging in size from small to large grapes and scatter all over the top of the pie. There is a lot of streusel; use it all, gently mounding it in the center.
7. Finish baking the pie: Return the pie to the oven and bake for 15 minutes more. Turn the heat down to 350 degrees and continue baking for 20 to 30 minutes more, or until the streusel is evenly browned and the pie feels firm when gently pressed. If you can see any filling bubbling around the edges, that is a good sign of doneness, but most likely it will be completely covered with streusel.
8. Cool the pan on a rack to allow the filling to thicken and set. Serve at room temperature.