Bring a large pot of water (at least 4 quarts) to a boil and season it generously with a tablespoon of salt. Add the green beans and cook to blanch for 3-5 minutes, or until the beans are just tender crisp. Drain well and transfer the beans to an ice water bath to stop the cooking (this will also help retain the bright green color).

Meanwhile, brown the butter. Add the butter to a small pan or pot with a light color bottom (this will allow you to see when the butter solids have turned golden). Cook over medium heat until the butter smells nutty and the solids in the butter have turned a light golden color. Add chopped hazelnuts and continue to cook until the butter is a medium golden color and the nuts are toasted. Remove butter from heat and set aside.

Arrange green beans on a plate, spoon brown butter and nuts over top. Squeeze lemon over top and sprinkle with zest, parsley, and salt and pepper, to taste.