Heat large covered saucepot of salted water to boiling over high heat. In food processor with knife blade attached, pulse garlic until chopped. Add bread and process 15 seconds or just until coarse crumbs form. In large skillet, melt 2-1/2 tablespoons but
Meanwhile, add green beans to boiling salted water and return water to boiling. Reduce heat to medium and cook 5 minutes or until crisp-tender; drain beans.
In same saucepot, melt remaining 2-1/2 tablespoons butter over medium heat. Stir in mustard, lemon juice, remaining 1/2 teaspoon salt and pepper. Add green beans and toss to coat. Add breadcrumb mixture and toss until well combined.