Bring a large pot of salted water to a boil. Add the trimmed green beans and cook for 2 to 3 minutes until they turn bright green and are just barely tender when you pierce one with a fork. Drain immediately in a colander and set aside. If you want to keep them extra crisp, run cold water over them for 30 seconds to stop the cooking.

Set your large skillet over medium heat. Add the sliced almonds in a single layer with no butter or oil. Toast them, stirring constantly, for about 60 to 90 seconds until they are golden and smell nutty. Watch them closely because they go from golden to burnt very fast. Tip them into a small bowl and set aside.

Return the skillet to medium-high heat and add 2 tablespoons of butter. Once the butter melts and starts to foam, add the sliced shallots. Cook, stirring occasionally, for about 2 minutes until the shallots soften and the edges start to turn golden.

Add the drained green beans to the skillet. Sprinkle with garlic salt and black pepper. Toss everything together using tongs or a wooden spoon and cook over medium-high heat for 3 to 4 minutes, stirring occasionally, until the beans are heated through and some of the tips pick up a little char from the hot pan. That slightly blistered look is exactly what you want.

Remove the skillet from the heat. If using lemon juice, drizzle it over the beans and toss quickly. Scatter the toasted almonds over the top and transfer to a serving dish right away so the almonds stay crisp.