In a pot, combine 10 cups water and the butterbeans, and bring to a boil. Reduce the heat to low, cover, and simmer for 1 1/2 hours or until the beans are just tender. Drain the cooked butterbeans, reserving the cooking liquid for making soups, and set aside the drained beans. Meanwhile, in a saucepan, bring the remaining 3 cups water to a boil. Add the pearl onions and cook them in the boiling water for 2-3 minutes to loosen the skin. Drain the pearl onions and set aside to cool. When the pearl onions are cool enough to handle, peel off the outer layer from each and discard it.

Lightly oil (or spray with a light mist of oil) a 15x10-inch baking dish. Layer the green beans, pearl onions, garlic, thyme, and salt, and then drizzle the olive oil over the top and toss gently to combine. Bake at 375 degrees for 15 minutes. Remove the pan from the oven, add the cooked butterbeans, toss gently, and bake an additional 8-10 minutes or until the green beans are crisp-tender. Remove the pan from the oven, drizzle the remaining ingredients over the top of the vegetables, toss gently, and transfer to a large bowl for service.

Serves 8-10