- 1 ¾ cup graham cracker crumbs
- ¼ cup granulated sugar
- ¼ teaspoon salt
- ⅓ cup unsalted butter, melted
- ½ cup unsweetened coconut flakes
- ¾ cup sugar
- 3 tablespoons cornstarch
- 1 ½ cups grapefruit juice
- 3 egg yolks
- 6 tablespoons butter, cut up
- 1 drop red food coloring
- ¼ cup toasted coconut flakes
- 2 tablespoons chopped dry roasted pistachio nuts
- Heat oven to 400°F, and grease a long rectangular tart pan (or a 9-inch round tart pan), set aside.
- Combine the graham cracker crumbs, sugar and salt in the bowl of a food processor. Pulse until combined.
- Drizzle the melted butter over the mixture and pulse until combined and mixtures looks like wet sand.
- Transfer to a bowl and mix in the coconut flakes.
- Press into the bottom of the prepared pan. Bake the crust until set, about 5-8 minutes or until lightly browned. Transfer to a rack and let cool completely.
- In a medium saucepan set over medium heat, combine the sugar with the cornstarch and add in the juice. Cook, stirring, until thickened and bubbly.
- Gradually whisk in half of the hot mixture into the egg yolks to temper the eggs. Return the egg mixture to the saucepan and cook, stirring constantly, until the mixture thickens, about 2-3 minutes.
- Remove from heat and add in the butter pieces. Whisk until melted. Stir in food coloring if using.
- Pour the mixture into the cooled crust and smooth the top with a spatula. Cover with plastic wrap pressed against the top of the tart and chill for at least 4 hours, preferably overnight until set.
- To serve, top with coconut flakes and pistachios.