You can make most of it ahead of time. I'd suggest blanching the beans, as described above, then storing them in the fridge. You can prepare the other ingredients ahead, as well. Grate the Parmesan, chop the pecans, grate the lemon zest and mince the garlic. Then just before serving, you can quickly stir fry the ingredients in a skillet, garnish with lemon zest and serve piping hot!