Make the pastry

Cup of Yum
1. Using a stand mixer fitted with the paddle attachment, cream butter, sugar, and salt on medium speed until pale and light, 2 to 3 minutes. Scrape the sides and bottom of the bowl with a rubber spatula.
2. Add flour and beat on low speed until combined, 15 to 30 seconds. The mixture will look like wet sand.
3. Add egg yolk and vanilla and continue to mix on low speed until the dough comes together.
4. Flatten dough into a 6-inch (15-cm) disc, wrap in plastic, and refrigerate for at least 1 hour.
5. Once dough is chilled, lightly coat tart pan with baking spray.
6. Remove dough from refrigerator and let soften at room temperature for about 10 minutes. Using a rolling pin, bang and flatten the dough into a disk about 1/2-inch thick. Flour the work surface, then sprinkle the disk with flour. Roll out dough into a 12-inch (30-cm) circle.
7. Carefully wrap dough circle around pin, then unfurl it over the tart ring. Press into the bottom and up the sides of the pan, using any scraps to patch tears or fill in missing bits. Trim edge with a knife so it's even with the rim of the pan.
8. Refrigerate for at least 30 minutes. 
9. Meanwhile, position a rack in the center of the oven, and crank the heat to 350°F (176°C).
10. Line tart with foil and fill to the top with granulated sugar. (Granulated sugar is the best pie weight. Plus after a few uses you get lovely toasted sugar!)
11. Bake for 30 to 35 minutes, or until golden brown. Move to a cooling rack, remove foil and sugar, and let cool completely in the pan.

Make the apple-butter custard

1. In a medium saucepan, whisk together sugar, cornstarch, and salt.
2. Add yolks and whisk thoroughly into a smooth paste.
3. Gradually add the milk until well incorporated.
4. Heat mixture over medium heat and whisk constantly until custard comes to a gentle boil. It will "burp" or "wink" as small bubbles rise to the surface.
5. Once the custard is boiling and burping, cook for 1 full minute more, whisking the whole time. The cornstarch needs the full minute of boiling to set the custard.
6. Whisk in apple butter and continue cooking for another minute. Stir in butter and vanilla and remove from heat.
7. Immediately pour custard into a shallow bowl and press plastic wrap directly on the surface. Chill at least 3 hours or overnight.

Make the apple roses

1. In a medium pan, bring water, sugar, and lemon juice to a boil. Whisk to dissolve sugar. Slide pan off heat.
2. Meanwhile, cut 1 or 2 apples in half from stem to blossom end. Place an apple half cut side down to steady it. Starting from one side, slice apple into half moons, no thicker than 1/8 of an inch. When you reach the core (you'll feel the seeds as you cut), turn the apple around, and repeat on the other side. (Don't discard the bit of leftover apple. Munch!)
3. Dunk apple slices in the hot liquid until just pliable enough to roll into roses, 15 seconds to 1 minute, depending on their thickness. Remove half moons with a slotted spoon and transfer to a plate.
4. Curl an apple half moon around itself to start a rosebud. Keep adding petals to the outside to build a rose. If needed, skewer rose with a few toothpicks to hold petals in place. Place rose on a plate.
5. Repeat with remaining apples until you have enough roses to cover the tart. You may have to reheat the syrup when adding more apples.☞ TESTER TIP: Not in a rosy mood? No harm, no foul. Overlap apple slices in concentric circles (as in the far end of the pictures above) to cover the tart. If not serving the tart within an hour or so, cover roses with plastic wrap and refrigerate.

Assemble and serve

1. Whisk apple-butter custard to make it smooth.
2. Fill crust with custard, smoothing the top with a spatula.
3. Remove toothpicks from apple roses and plant them on the tart. Carry to the table and watch everyone's mouth drop!