The first time I had one of these was at Texas Renaissance Faire. Since it’s a sandwich, you can pretty much make it however you want. This is how we like ours:
Everything Bagel (slightly warmed)
Onion & Chive Cream Cheese
Red Onion, thinly sliced
Cucumber, thinly sliced
Roma Tomato, thinly sliced
Spread a thin layer of cream cheese on each side of the bagel. Layer onions, cucumber, tomato and avocado. Top with sprouts.
If the avocado is pretty ripe, I will spread it on the bagel, instead of the cream cheese.