While the asparagus roasts, make the pesto. Add the garlic, parsley, spinach, lemon juice, dill, feta, pine nuts, and olive oil. Add a pinch of salt, pepper, and red pepper flakes. Pulse until it becomes a smooth, creamy sauce.
1 large pinch salt, 1 pinch pepper, ¼ cup olive oil, ½ lemon, 2 tbsp pine nuts, ¼ cup fresh parsley, ¼ cup fresh dill, 4 tbsp feta cheese, 2 garlic cloves, red pepper flakes, ⅓ cup spinach