Preheat the oven to 300 degrees and set a rack in the middle.
In a small mixing bowl, combine the graham cracker crumbs, 1/2 cup of the sugar, and the melted butter. Divide the mixture among 4 (1-cup) custard cups and press down to form a crust on the bottom.
In a small saucepan over medium heat, combine the cream and 1 tablespoon of the remaining tablespoon of sugar. Scald and remove from the heat. In a large mixing bowl, combine the yolks, the remaining tablespoon of sugar, vanilla, and rum. Whisk lightly, just to combine.
Whisking lightly, gradually drizzle the scalded cream mixture into the egg mixture to warm it without scrambling the eggs. Strain the mixture and pour into custard cups. Place 6 raspberries in each cup, dunking them so they are coated with custard.
Arrange the cups in a roasting pan and pour in hot water halfway up the sides. Cover the pan with foil and bake for 30 to 40 minutes, or until the custards are set. Cool in the pan, then refrigerate, covered, up to 2 days ahead.
If you like, sprinkle a light layer of sugar over each custard and place under a preheated broiler for about 2 to 4 minutes, watching that they don't burn. Serve immediately after glazing.