For crust:

1. Cut butter into cubes.
2. Place in bowl of food processor.
3. Add flour, sugar and salt.
4. Pulse for 30 seconds until it resembles a crumb texture.
5. Stir together yolks and water.
6. Drizzle into processor while pulsing.
7. When mixture begins to bind together, pour contents onto work surface.
8. Press together to shape into a ball.
9. Divide into 12 equal-sized discs.
10. Wrap in plastic. Refrigerate for 30 minutes until firm.
11. Roll out a dough disc. Press into a nonstick mini-tart pan.
12. Gently press and shape dough into bottom and sides of pan.
13. Set pan on a rimmed baking sheet.
14. Repeat with remaining dough.
15. Prick the pastries all over with a fork to prevent dough from puffing.
16. Chill in fridge for 30 minutes.
17. Preheat oven to 400° F. Bake for 20 to 25 minutes until edges are lightly golden and center is cooked through.
18. Let cool completely.

For custard:

1. Place oil in medium bowl.
2. Set a fine-mesh sieve over top; set aside.
3. Scrape vanilla seeds into a heavy medium saucepan.
4. Add vanilla pod and milk.
5. Bring to a simmer over medium heat.
6. Cook, stirring occasionally, until milk reduces to about 1 cup (about 10 to 15 minutes).
7. Add half-and-half. Bring to a gentle simmer.
8. Meanwhile in another medium bowl, briskly whisk the egg, yolks, cornstarch, salt and sugar until pale and thick (about 1 minute).
9. Whisking constantly, slowly pour 1/2 cup of hot milk mixture into egg mixture.
10. Continue whisking milk mixture in saucepan.
11. Slowly pour tempered egg mixture into saucepan.
12. Cook on medium heat, whisking constantly, until foam subsides (about 2 minutes).
13. Custard should hold whisk marks.
14. Immediately scrape custard into sieve.
15. Use a spatula to press mixture into bowl with oil.
16. Remove vanilla pod. Whisk strained custard until oil is incorporated and mixture is glossy and smooth.
17. Set bowl inside a large bowl of ice-water. Whisk occasionally until custard is cool (about 3 minutes).
18. Divide custard evenly into cooled tart shells.
19. Chill until set.
20. When ready to serve, place pineapple rings on a baking sheet.
21. Stir brown sugar and rum together. Brush on top of pineapple.
22. Place under broiler for 5 minutes or until sugar begins to caramelize.
23. Let cool completely. Place a pineapple ring on top of each tart. Garnish with coconut flakes before serving.