Step 1: In a stand mixer fitted with a whisk attachment, beat in the butter, sugar and salt on medium speed until pale and creamy, about 2 minutes.
Step 2: Scrape down the sides and bottom of the bowl with a rubber spatula.
Step 3: Add the flour and mix on low speed for about 30 seconds until the flour is incorporated. The mixture will look like wet, clumpy sand. Add the egg yolk and mix on low speed until the yolk is evenly incorporated and the dough is lumpy about 30 seconds.
Step 4: Using your hand, lightly knead the dough into a ball in the bowl. Remove the dough from the bowl and press it into a 15cm disc, wrap it tightly in cling film and leave it in the fridge for about 30 minutes. (The dough can be wrapped tightly in cling film and stored in the fridge for up to 5 days or in the freezer for up to 3 months. If frozen, thaw in the refrigerator overnight before using.)
Step 5: Butter your pan and place the cooled dough in it.
Step 6: Pinch off pieces of the dough and press them against the sides of the pan to just under 1cm thick and leave it hanging over the edge (you will cut the top off later).
Step 7: With the heel of your hand, press the remaining dough evenly into the bottom of the pan (it will look messy, and it may look like you don't have enough dough at first, but trust that it will come together). Be sure there are no holes in the dough and press it squarely along the corners where the bottom meets the sides to avoid thick edges. Using a paring knife, trim the top edge of the dough to flush with the edge of the pan.
Step 8: Cover with cling film and place in the freezer for at least 30 minutes to cool.
Step 9: Preheat oven to 350°F and place an oven rack in the middle position.
Step 10: Assemble the pie: Remove the pie ring and transfer the pie shell to a serving dish.
Step 11: Whip cream ingredients until smooth, then spread evenly over pie shell with a spatula.
Step 12: Arrange a generous amount of fruit on top of the custard in the desired decor.
Step 13: Enjoy!