Preheat the oven to 375 degrees. Line a baking sheet with parchment paper and set aside.
Place the Simply Potatoes Traditional Mashed Potatoes, green onions, 1 cup shredded mozzarella, 2 cloves finely grated garlic, and crumbled bacon into a stand mixer fitted with a paddle attachment. Mix the ingredients together for 1-2 minutes until well combined and fluffy. Set aside.
Place the olive oil, garlic salt, and baby spinach into a large skillet. Cook over medium-low heat until the spinach wilts and the volume reduces by 3/4, about 2-3 minutes. Be sure to stir the spinach frequently.
Slice each pie crust sheet in half, for a total of four halves. Evenly distribute the spinach over each dough half. When spreading the spinach on each dough piece, use only half of each piece, leaving the other half empty, as it will be folded over. You should also leave a border of clear dough in order to seal the crust later. Top the spinach with 1/4 cup mozzarella and a half cup of the potato mixture. Fold the crust over the filling. Press the edges together, then crimp the edges as you would when making a traditional pie. Place each calzone onto the prepared baking dish. Brush the tops with melted butter.
Bake for 30-35 minutes, until the crust is golden brown. Allow to cool for at least 5 minutes before serving.