Grease muffin tin using nonstick spray or olive oil. Heat olive oil in a medium skillet over medium-high heat. Add mushrooms and saute for about 3 minutes. Add the kale and shallots and saute another 2 minutes. Set aside and cool.
In a medium bowl, whisk the eggs. Add the salt, pepper, swiss cheese and mushroom kale mixture. Using a spoon, fill muffin cups evenly with egg mixture.
Bake for 15-18 minutes until eggs are cooked through and not jiggly.
Allow to cool for 5 minutes before removing from tins. Store in airtight container in fridge for up to 1 week. Microwave 30 seconds to reheat.
Good Thyme Tip: You can also use paper muffin cups for easy clean up!
Recipe by Good Thyme Kitchen at https://www.goodthymekitchen.com/mushroom-kale-egg-muffins/