Heat the oven to 300 degrees F. Saute the corn in the butter in a skillet over medium-high heat, until lightly browned. Set aside to cool. Heat the cream, half-and-half, and vanilla bean in a saucepan over medium heat just until it comes to a boil. Immediately turn off the heat and set aside to infuse for 10 minutes. Whisk the egg yolks with 1/2 cup granulated sugar in a large bowl just until combined. Whisking constantly, gradually pour in the hot cream mixture. Strain the custard mixture into a pitcher to smooth it and to remove the vanilla bean. Divide the corn among ramekins or soup plates then top them off with custard. Arrange them in a hot water bath; the water may be very shallow, but that's fine. Bake in the center of the oven until set, 30 to 35 minutes. Remove from the water bath and let cool 15 minutes. Tightly cover each custard with plastic wrap, making sure the plastic does not touch the surface. Refrigerate at least 2 hours. When ready to serve, preheat a broiler to very hot (or fire up your kitchen torch). Sprinkle the surface of the custard with an even layer of coarse sugar and place the dishes on a baking sheet. Broil or torch the surface until the sugar is melted and well browned, about 1 minute. Let cool slightly and serve immediately.