Preheat oven to 375°F (190°C).

In a large skillet, heat olive oil over medium heat.

Add chopped onion and green pepper and sauté until softened, about 5 minutes.

Add chopped garlic and cook for 1 minute more.

Stir in the canned green beans, salt, pepper, sage, and oregano.

Cook for another 5 minutes, stirring occasionally.

In a separate bowl, whisk together the eggs, Parmesan cheese, and sherry.

Pour the egg mixture over the green bean mixture in the skillet.

Sprinkle bread crumbs evenly over the top.

Bake in the preheated oven for 20-25 minutes, or until the frittata is set and golden brown.

Let cool slightly before slicing and serving.