Finely chop 2 cups of leftover or deli brisket. In a saucepan, combine BBQ sauce, apricot preserves, brown sugar, and garlic powder, heating until bubbly, then let cool.
Slice Hawaiian rolls, place bottoms in a baking dish, add brisket, sauce, and Swiss cheese, then top with remaining rolls, brush with butter, sprinkle with Everything Bagel Seasoning and parsley.