Preheat the oven to 400F.
In a frying pan, heat half of the olive oil and saute the garlic and rosemary with the tomato paste and cayenne for about a minute.
Add the green beans and cherry tomatoes, sprinkle in salt and pepper, and pour in 1/2 cup water. Bring to the boil, cover and simmer for 10 minutes.
While the vegetables simmer, toss together the panko, Parmesan and parsley.
Remove the cover of the frying pan and turn off the heat. Taste the vegetables and add more salt and pepper, if needed.
If your frying pan is NOT over-safe, scrape the vegetables and juices into a baking pan (read more details after the recipe). Sprinkle the panko mixture over the vegetables. Drizzle the remaining olive oil evenly over the topping.
Bake the beans and tomatoes, uncovered, at 400F for ten minutes or just until the pan juices bubble and the topping is lightly browned.