In a 9x13 baking pan (will look too big, but this lets some of the juice from tomatoes evaporate), add tomatoes, butter, ¼ teaspoon salt, black pepper, thyme, garlic. Stir to submerge the thyme. Place in oven and bake for 10 minutes, then pull out and stir to disperse melted butter. Place aluminum foil over the top and bake for another 20 minutes.
Meanwhile, heat large pan on stovetop to medium heat, and add 1½ tablespoons olive oil. Add kale and ¼ teaspoon salt, and cook for 8 minutes on medium heat, until very soft and tender, adding a tablespoon or two of water if needed.
When tomatoes are done, remove thyme and discard.
Stir in remaining ¼ teaspoon salt, kale, and beans so everything is coated.
In a small bowl, stir remaining 1½ tablespoons olive oil into breadcrumbs, and top gratin with this. Bake at 350 degrees for another 8 minutes, uncovered,then broil for 2 minutes until topping is golden brown. Serve warm, and drizzle a little olive oil over each serving (the fat is important to pull it all together).