HEAT butter and brown sugar to a boil in small saucepan over medium heat. Remove from heat and stir in pecans. Set aside.
GREASE a baking sheet with butter. Place the bread slices on the baking sheet. Bake for 5 minute Or until lightly toasted. Remove from sheet and set aside.
BEAT milk, eggs, granulated sugar and vanilla in medium bowl. Dip 8 slices toast into the batter and place on baking sheet. Spread a heaping tablespoons Of the pecan mixture onto each. Dip remaining slices toast into batter and place over nut filling to form a sandwich.
BAKE for 20 minute Or until hot. Sift confectioners' sugar over toast. Serve immediately.