Preheat oven to 350 degrees. Heat olive oil in saute pan on medium high heat. Dump spinach into pan, add onion powder, toss together, and cover and cook until spinach is wilted (about 2 minutes). Remove spinach from pan and set on paper towel to drain. If desired, saute prosciutto until crispy, and remove from heat.
In a medium bowl beat eggs and heavy cream, and season with fresh pepper and a pinch of salt. Add cheese to eggs and mix well. Spray your muffin pan with olive oil spray to prevent sticking. Evenly distribute spinach and prosciutto into muffin cups. Evenly pour the eggs in the muffin cups over the spinach and prosciutto. Cook for 20-25 minutes at 350 degrees. Serve immediately using a dull knife to easily get egg cupcakes out of the muffin pan.