1Spray closed medium-size contact grill with cooking spray; heat for 5 minutes. Spread 1 tablespoon hazelnut spread over 1 side of each bread slice. Sprinkle 6 slices evenly with hazelnuts. Top each with second bread slice, making 6 sandwiches.
2In shallow bowl or pie plate, beat half-and-half, eggs and vanilla until well blended.
3Dip 3 of the sandwiches into egg mixture, turning to coat both sides. When grill is heated, place sandwiches on grill. Close grill; cook 2 to 3 minutes or until golden. Repeat with remaining sandwiches. Sprinkle with powdered sugar, if desired.