- Bring 4 quarts water to a boil in a large Dutch oven over medium-high. Add green beans; cook until crisp-tender, 4 to 5 minutes. Drain beans; plunge into a large bowl filled with ice water to stop the cooking process. Drain beans, and dry thoroughly with paper towels.
- Wipe Dutch oven clean; add butter and oil, and cook over medium-low until butter is melted.
- Add almonds, and cook, stirring constantly, until the butter has browned and almonds are beginning to brown, about 5 minutes.
- Add garlic, and cook, stirring constantly, 1 minute. Stir in lemon juice and 2 tablespoons water.
- Cook, stirring constantly, until the sauce has thickened slightly and has a glossy sheen. (Add up to 1 more tablespoon water if sauce is too thick.)
- Stir in beans, salt, and pepper. Increase heat to medium; cook, tossing occasionally, until beans are hot and coated with sauce and almonds, 4 to 5 more minutes.