Make the Ginger Shortbread Crust (see note below about decorative cookies):

1. Add the flour, almond flour, powdered sugar, ginger, and salt to the bowl of a food processor and pulse 2-3 times to combine. Add in the butter and pulse 5-7 times, or until the butter is broken down into tiny pebbles.
2. With the motor running, add in the egg and let the dough process until it forms together into a cohesive ball around the blade, about 1 minute.
3. Remove the dough from the processor and shape it into a disk. Wrap it in plastic wrap, then chill it for at least 30 minutes.

Roast the Squash:

1. While the dough is chilling, preheat the oven to 400ºF and place oven racks in the middle and lower parts of the oven. Line a rimmed baking sheet with parchment paper.
2. Wash and dry the honeynut squashes. On a sturdy cutting board, cut each squash in half lengthwise.
3. Scoop out the seeds and stringy bits and discard.
4. Place each squash cut-side down on the prepared baking sheet.
5. Bake on the middle rack for 20 minutes. Flip the squashes cut-sides up and bake for another 15-30 minutes (it will vary greatly depending on the size of your squash), or until they are fork tender. Once tender, remove from the oven and let cool. 

Shape the Tart Shell:

1. Reduce the oven temperature to 375°F. Remove the chilled dough from the refrigerator and place on a flour-dusted work surface.
2. Roll out the dough to an 11-inch circle and place it in a 9-inch tart pan, making sure to push the pastry into the edges of the pan. Trim off any excess dough. Place the tart shell in the freezer for at least 15 minutes.
3. Once chilled, line the tart shell with a round piece of parchment paper, then add pie weights (or dry rice or beans or lentils), making sure to push the pie weights to the edges.
4. Bake on the lower rack for 20 minutes, then remove from the oven and carefully remove the parchment and pie weights. Return to the oven and bake for an additional 5 minutes, or until the pastry is fully cooked through. Set aside until ready to use. 

Make the Filling, Assemble, and Bake:

1. While the tart shell is chilling and baking, scoop out the roasted squash flesh from the skins. Place 15 ounces (about 1-¾ cups) of the roasted squash in a clean food processor or high-speed blender. Save any remaining squash for another use. Purée the squash until completely smooth, scraping down the sides as necessary.
2. After the tart shell has been blind-baked, lower the oven to 325ºF.
3. To the food processor with the honeynut puree, add the egg yolks, crème fraîche, sugar, ginger, vanilla extract, and salt. Process until smooth.
4. Transfer the filling into the prepared tart shell and smooth over the top.
5. Bake on the middle rack for 40-45 minutes, or until the filling has a matte appearance and has slightly puffed up on the edges. There should be no wobble in the middle of the tart.
6. Remove the tart from the oven and transfer to a wire rack to cool to room temperature. Transfer to the refrigerator to chill for at least 4 hours.
7. The tart can be garnished with pie crust cookies (see notes for instructions) or with whipped cream!