Preheat the oven to 350°F (180°C)
Grease muffin pan with olive oil
In a large bowl, whisk eggs with milk, add salt and pepper to taste
Chop the sundried tomatoes and spinach into smaller pieces
Place the vegetables into the bottom of each muffin cup
Pour egg mixture over the vegetables, until each cup is about ¾ full
Crumble feta cheese on top of each muffin cup
Bake for 20 minutes, until the egg muffins are set
Let cool for a few minutes, then use a knife to scrape around the edges to loosen the muffin from the pan. Enjoy!