Preheat the oven to 350°F (175°C).
Spread the 1 1/4 cups sweetened flaked coconut on a large baking sheet and toast in the oven, stirring twice, until golden brown, 6 to 8 minutes. Remove from the oven. Lower the oven temperature to 300°F (150°C) or turn it off for a spell and then preheat it again.
Bring the 1 1/2 cups heavy cream, toasted coconut (from step 8), and 3/4 cup half-and-half to a rolling boil in a large saucepan over medium heat. Immediately remove from the heat, cover, and let steep for 35 minutes.
When you're ready to bake the tart, in a large bowl, whisk together the 6 large egg yolks, 2 tablespoons turbinado sugar, and a pinch of salt. Still whisking constantly, slowly add the cream mixture. Pour the mixture through a fine strainer set over a large glass measure, pressing hard on the solids to extract as much liquid as possible.
Place the tart pan on a baking sheet. Pull the oven rack out slightly, place the baking sheet on the rack, and pour the custard into the tart pan. Bake for 25 to 30 minutes, until just barely set. Watch the custard closely at the end, as it can set and overcook quickly. Keep in mind, the custard will continue to set as it cools. Remove the tart from the baking sheet and let cool completely on a wire rack.
Just before serving, remove the side of the pan from the tart. Gently blot the surface of the custard with the edge of a paper towel to remove any condensation. Sift the 1/4 cup turbinado sugar evenly over the custard. Move the flame of a blowtorch evenly back and forth just above the top of the tart, avoiding the crust, until the sugar is evenly browned. Let stand for about 5 minutes before serving. Cut into wedges and serve with raspberries, if desired.