Preheat the oven to 400 degrees F.
Coat a 6-cup baking dish lightly with cooking spray and set it aside.
Place a non-stick pan over medium-high heat and melt 1 tablespoon of butter.
Add the bell pepper and onion and cook stirring for 3 minutes or until softened.
Add the garlic and cook for 30 seconds. Remove the vegetables to a plate and set aside.
Wipe out the pan with a paper towel and add the remaining butter.
Season the steak with salt and pepper and add it to the pan. Cook for 4-5 minutes, stirring occasionally. Season with more salt and pepper while you cook it.
Add the paprika and Worcestershire sauce until the steak is browned and mostly cooked through.
Remove the steak pieces from the pan and if needed chop them a bit more.
In a medium bowl, beat the cream cheese with a mixer until smooth. Add the sour cream and mayo and beat until combined.
Add the vegetables and steak to the cream cheese mixture and fold them using a spatula.
Stir in half of the cheese.
Spread the dip into the prepared pan and sprinkle with the remaining cheese on top.
Bake for 15-20 minutes or until the dip is bubbly and the cheese is melted.
Broil the top for 1-2 minutes to brown the cheese.
Sprinkle with parsley and serve hot with crostini and celery sticks on the side.
