Put the broccolini in a resealable plastic bag and add the garlic, 1 1/2 tablespoons olive oil and 1/4 teaspoon salt. Seal the bag and massage the oil and garlic into the broccolini. Pour the broccolini and garlic into a medium baking dish.
Pulse the bread in a food processor until finely chopped. Add the olives, red pepper flakes, 1/4 teaspoon salt and 1 tablespoon olive oil. Pulse until the olives are finely chopped and the crumbs well-coated in oil.
Pour the breadcrumb mixture over the broccolini and bake until the broccolini is crisp-tender and the breadcrumbs are golden brown, about 20 minutes.