Heat a large skillet over medium-high heat. Melt butter, then stir in the shallots. Sauté until tender, about 3-4 minutes. Season with salt and pepper.
Toss the cherries in the pan and cook while stirring for about 4 minutes, until softened and broken down a bit. Remove from heat.
Add mixture to a large bowl and stir in the baguette, chicken stock, wine, pistachios, and parsley. Give another seasoning of salt and pepper. Let cool completely.
Heat oven to 425 degrees.
Butterfly your pork roast by taking a sharp knife and cutting down the center of the roast, opening it up like a book, and leaving about 2 inches on the side so that you’re not cutting all the way through. Open the pork up and pound with a meat mallet so you have an even thickness. Season the inside with salt and pepper, then spoon the stuffing down the center. Roll the pork up like a jelly roll, then tie with butcher’s twine every 2 inches.
Place roast fat-side-up on a rimmed baking sheet lined with foil. Drizzle with olive oil and season generously with salt and pepper. Roast pork for 30 minutes. Lower the heat to 350 degrees and roast for another 25 minutes, or until a meat thermometer reads 145 degrees.
Let rest for 15 minutes before slicing and serving.