Pour just enough olive oil in a saucepan so that it flows when the pan is tipped. Heat it until it shimmers, then add the onions. Cook until they brown lightly, without stirring much. (It's good if they stick to the pan a bit.)
Add a few tablespoons of water to the pan and stir until the onions break loose from the bottom. Add the remaining olive oil, the garlic and the parsley. Cook until the garlic is fragrant.
Add the green beans and artichokes. Cook until thoroughly heated and steam is rising from the pan, stirring to mix the ingredients well.
Add the Parmesan cheese, half of the bread crumbs, salt, pepper, and Tabasco. Stir until just blended. The mixture should glisten a little with oil. If it doesn't, add more olive oil, a little at a time, stirring as you do. Taste and add more salt and pepper as needed.
Spoon the mixture into a baking dish. Cover with the remaining bread crumbs. Drizzle melted butter over the top. Bake at 350 degrees for 20-25 minutes.