Heat a skillet over medium-high heat and add prosciutto. Saute for a few minutes stirring often.
Add the kale and tomatoes and cook for another 3-4 minutes or until kale starts to wilt. Remove from heat.
Spray the bottom of one muffin tin with cooking spray.
Add 2 tbsp or so of the filling into each muffin well.
In a medium bowl add 10 eggs and 1/2 cup milk. Add salt and pepper and whisk really well until all eggs are mixed.
Carefully pour into each muffin well. Fill about 3/4 full.
Bake for 25 minutes or until quiche cups are set. Remove from oven and serve immediately. If using for meal prep, let cool and store in plastic container in fridge for up to three days.