Bring a large pot of generously salted water to a boil. Add the trimmed green beans and cook for 3 to 4 minutes, until they are bright green and crisp-tender.

Drain the beans and immediately transfer them to a bowl of ice water. Once cool, drain again and pat them dry so they do not dilute the brown butter.

Melt the unsalted butter in a large skillet over medium heat. Swirl the skillet occasionally and cook for about 3 to 5 minutes, until the milk solids turn golden brown and the butter smells nutty.

Add the minced garlic, if using, and cook for about 30 seconds. Watch closely because both the garlic and browned butter can burn quickly.

Add the blanched green beans, kosher salt, and black pepper. Toss for 2 to 3 minutes, until the beans are hot and evenly coated.

Remove the skillet from the heat and add the lemon juice and lemon zest. Toss once more, then finish with toasted almonds and Parmesan if desired.