Preheat the oven to 350ºF.
FOR THE MACAROONS:
Thoroughly combine the coconut, vanilla, and condensed milk in a large mixing bowl. Spoon the mixture, by tablespoon, onto parchment-or waxed-paper-lined baking sheets about 1/2 inch apart. Bake until lightly toasted and golden, about 15 minutes.
Remove the macaroons from the oven and transfer them to a wire rack. Let cool completely. Leave them out, lightly covered with parchment or waxed paper, for about 12 hours.
FOR THE FILLING:
Combine the milk, sugar, and vanilla in a large heavy-bottomed or nonstick saucepan over medium-high heat. Whisk to dissolve the sugar. When the mixture comes to gentle boil or simmer after 5 minutes, take 1 cup of the milk-and-sugar mixture and add it to the yolks. Whisk to blend well. Slowly add the yolks to the milk-and-sugar mixture in the saucepan, whisking constantly. Cook over medium heat until it thickens slightly, 4 to 5 minutes, whisking occasionally.
Dissolve the cornstarch in the water. Over medium heat, slowly add this mixture to the saucepan, whisking constantly for 1 minute. Using a wooden spoon, continue stirring for about 2 minutes. Add the coconut and continue stirring for 2 more minutes. Add the butter and stir until it is completely melted and the mixture has thickened to a custard, about 2 minutes.
Pour the mixture into a glass bowl. Cover with plastic wrap, pressing the wrap down on the surface of the custard to prevent a skin from forming. Cool completely and chill for at least 4 hours.
TO ASSEMBLE THE TRIFLE:
Beat the cream with an electric mixer on high speed for about 2 minutes. Add the sugar and beat until the mixture is thick and forms soft peaks, 1 to 2 minutes. Set aside.
Beat the coconut cream with a wire whisk until it is smooth. Set aside.
Pour the Grand Marnier into a small bowl. Dip each macaroon in the liqueur, submerging for 2 to 3 seconds, then transfer them to a sheet of parchment or waxed paper.
Spread 1 cup of the coconut cream filling on the bottom of a large, deep glass trifle bowl. Top the cream filling with 8 to 10 macaroons, placing them snugly against each other. Arrange 2 pints of the raspberries on top of the macaroons. Spread 2 cups of the coconut cream on top of the raspberries. Top with more macaroons, then 2 pints of raspberries. Spread another 2 cups of the coconut cream and top with the remaining macaroons and raspberries. Spread the remaining coconut cream on top of the raspberries. Mound the whipped cream evenly over the top.
Serve immediately or keep chilled until ready to serve.
Yield: 10 servings