Preheat oven to 375. Lightly oil 2 qt. gratin dish.
Layer half of the potato slices in dish. Sprinkle with half teaspoon of sea salt. Spread kale over and scatter with peppers, garlic and olives. Add ½ teaspoon of herbes de Provence, remaining sea salt and ¼ teaspoon of pepper.
Bake 45 minutes, or until tender. Toss breadcrumbs with 1 tablespoon of olive oil. Uncover gratin, and sprinkle with bread cubes. Bake uncovered 15 more minutes.