Start by washing the green beans thoroughly. Trim the ends and cut them into 1 ½-inch pieces.
Fill a large pot with water and bring it to a boil. Add a pinch of salt, then carefully add the prepared green beans. Boil for about 3-4 minutes until tender-crisp.
Drain the green beans and immediately transfer them to a bowl of ice water to shock them. Let sit for a few minutes before draining again.
In a dry skillet over medium heat, add the chopped walnuts and toast for about 3-5 minutes until fragrant and golden brown.
In the same skillet, add the diced butter and minced garlic. Cook over medium heat until the butter is melted and the garlic is fragrant, about 1-2 minutes.
Add the drained green beans to the skillet with the lemon butter sauce. Toss to coat, then add lemon juice, salt, and walnuts. Mix well.
Remove from heat and gently fold in the dried cranberries, crumbled feta, and lemon zest.
