01 - Preheat oven to 350°F (180°C). Generously grease a 6-cup muffin tin with olive oil or melted butter.
02 - In a large mixing bowl, vigorously whisk eggs, milk or cream, salt, and black pepper until thoroughly blended.
03 - Gently fold in shredded cheese, smoked salmon, chopped onion or shallot, spinach, and dill until evenly distributed.
04 - Evenly distribute the mixture into the prepared muffin cups, ensuring each is filled approximately three-quarters full.
05 - Place muffin tin in the oven and bake for 18 to 20 minutes, or until the egg muffins are set and lightly golden on top.
06 - Allow muffins to cool in the tin for 5 minutes. Run a knife around the edges to release and carefully remove.
07 - Top each muffin with extra dill if desired and serve warm or at room temperature.