Place the cream cheese and butter in a stand mixer bowl and whip on medium speed for two minutes. Turn the mixer off and add the icing sugar. Mix on low until well combined.
Add the lemon zest and vanilla, turn the mixer up to medium-high speed, and whip for another 30 seconds, or until light and fluffy. Scrape down the sides of the bowl as needed. Set aside.
Preheat your oven to 375°F (190°C). Line the baking sheet with parchment paper right up to the edges, to contain any filling that may bubble over during baking.
Lightly flour your work surface and place the cold dough in the middle. Lightly flour the top of the dough and, using a rolling pin, roll it from the centre outward, aiming to get it round. Keep rotating the dough as you roll it, lightly flouring the surface underneath as well as the top as needed to prevent it from sticking. Roll the dough out to about 1/2 centimeter thick. Use a knife or a pizza wheel to round out the edges.
Place the circle on the lined baking sheet.
The edges might hang over the sides a bit. You can also make individual galettes by using asmall bowl or saucer as a guide (about 15 centimeters in diameter) to cut six circles out of the pie dough with a sharp knife. You may need to re-roll the scraps to get all 6 circles. Continue as directed, dividing the fillings evenly.
Spread the cream cheese filling over the pie dough, leaving about five centimeters around the edge. Fan the pears evenly over the filling. If your pears are large, you may not need all of the slices.
Mix the blueberries, sugar, cornstarch, and lemon juice together in a bowl. If your blueberries are frozen, wait a minute or two to allow some of the sugar and cornstarch to dissolve. Scatter them over the pears. If there are dry ingredients left in the bottom of the bowl, make sure to sprinkle them on top as well.
Starting on one side of the galette, fold the pastry edge over towards the middle. Do this around the galette, overlapping each edge and leaving a circle open in the centre. Press down on the edges firmly to seal up the sides, to prevent too much liquid from escaping during baking.
Whisk together the egg white and cream to make egg wash and generously brush it over the pie dough. Sprinkle the entire galette generously with sugar.
Bake for one hour to one hour and ten minutes, until the pastry is a golden brown and the filling in the centre is cooked and bubbling. Let the galette rest for at least 15 minutes before cutting. Serve warm or at room temperature.
Storage and serving:
This galette will keep at room temperature for up to a day or in the refrigerator for up to three days. It can be reheated in the oven before serving, but it’s best eaten freshly baked.
Easy mixer pie dough:
Place the flour, butter, shortening, and salt into a stand mixer bowl. Mix on low speed until the fats are in small chunks and the mixture looks a bit dry. This should only take 10 to 15 seconds. If you overmix you run the risk of turning your mixture into a dough, and then you’ll have a difficult time incorporating all the water into it in the next step.
Add the ice water all at once and mix on medium speed until the dough just comes together. Some small lumps of fat should remain in the dough.
Shape the dough into two flattened balls.
Wrap each ball in plastic wrap and refrigerate for at least 30 minutes, making sure the dough is fully chilled before rolling out. At this point the dough can be frozen. Let it thaw completely before using it, but when you roll it out, be sure it’s still cold.