Heat a non-stick skillet over high heat for one minute, add prosciutto and reduce heat to medium. Sauté for 2 minutes stirring often. Place prosciutto in large bowl and do not wash skillet. Add Simply Potatoes Shredded Hash Browns to the skillet and press down lightly until hash browns are flattened and spread out. Cook for 2 minutes without stirring over medium heat. Turn hash browns, press down again with the spatula and cook for 2 more minutes. Turn off heat and add the Simply Potatoes Shredded Hash Browns to the bowl with the prosciutto. Mix in the sour cream, pancake mix and Gruyere, saving out 1/2 cup of cheese for later. Mix together until well blended and spread evenly into a prepared 9 inch round non-stick cake pan.
Bake for 30 minutes, remove and let cool for 5 minutes. Preheat broiler to high heat and place rack in center of the oven. Run a knife around the edge of the potato pan to loosen and turn upside down onto a baking sheet, tap the top of the pan to loosen and carefully remove cake pan. Sprinkle top with the remaining cheese and place in oven for 2 minutes to brown. Watch carefully as not to burn.
Remove from oven, using a large spatula carefully place cake onto a serving platter. Slice in triangles to serve.