1/4 cup plus 1 tablespoon extra virgin olive oil
1 medium yellow onion, finely chopped (about 1 1/2 cups)
4 cloves garlic, finely chopped (about 4 teaspoons)
2 teaspoons finely chopped fresh rosemary
2 cups store-bought marinara sauce (I like Rao’s)
3 (15-ounce) cans butter beans, drained and rinsed
2 ounces crumbled feta cheese (about 1/2 cup)
1 1/4 cups panko bread crumbs
2 teaspoons chopped fresh thyme leaves
1 teaspoon kosher salt
1/2 teaspoon ground black pepper
Preheat the oven to 350°F, with a rack in the center position.
Heat 1 tablespoon of the olive oil in a 10-inch cast iron skillet over medium-high heat. When the oil is shimmering, add the onion and cook until just starting to brown, 5 to 7 minutes. Stir in the garlic and rosemary and sauté for another minute. Add the marinara sauce, beans, and feta, stirring to combine. Reduce the heat to low.
While the beans are heating on the stove, in a small bowl, mix together the panko, thyme, remaining 1/4 cup olive oil, salt, and pepper.
Generously sprinkle the bread crumb mixture over the skillet of beans. Transfer to the oven and bake until the beans are bubbling and the topping is browned and crisp, 20 to 30 minutes.
Serve hot, with lots of bread for sopping up the sauce.