Heat 7- to 8-quart saucepot of salted water to boiling on high. Meanwhile, fill very large bowl with ice and water. Add beans to boiling water; cook 4 minutes. Drain beans and add to ice water. (To make ahead, let beans cool completely; drain well. Transfer beans to resealable plastic bag; refrigerate up to 1 day.) In same saucepot, heat butter and oil on medium. Add shallots; cook 5 to 10 minutes or until lightly browned, stirring occasionally. Drain beans and add to pot, along with 1 teaspoon salt and 1 teaspoon freshly ground black pepper. Cook until beans are heated through, stirring occasionally.