Preheat the oven to 400℉. Whisk together the eggs, heavy cream, salt and pepper. Set aside.

In a 10-inch cast iron skillet over medium heat, cook the bacon until crispy. Remove with a slotted spoon and aside. When the bacon is cool enough to handle, crumber in small pieces. 

In the same skillet over medium heat, cook the onion in the bacon fat until caramelized, about 10 minutes. After the onions caramelize, add the grape tomatoes to the pan and cook for 1-2 minutes. Remove the pan from heat.

Add the egg mixture, bacon crumbles, and blue cheese crumbles to the pan, and mix to combine.

Bake for 40-45 minutes until a toothpick in the center comes out clean. Remove from the oven, and let stand for 2-4 minutes. Then, top with fresh chopped parsley and serve.

See post for storage options.