Chop the roasted peppers, thinly slice the onion, and finely chop the basil.
Add the chopped roasted peppers, finely chopped/minced basil, thinly sliced onion, minced garlic, salt, pepper, and 1 tablespoon of extra-virgin olive oil to a mixing bowl. Mix until everything is combined, and then set the bowl aside while moving on to the next step of toasting the bread/making the crostini.
Slice the loaf of bread into thick slices (about 12 slices) and brush the slices with olive oil on both sides.
Toast the bread for a couple of minutes on each side, either on a grill or grill pan.
Spoon the roast pepper topping on the toasted/grilled bread.
Top with goat cheese and arugula/rocket, and optionally, drizzle balsamic glaze over everything.