Preheat oven to 400°.

In a small saucepan over medium heat, combine 1 cup of the chicken stock and the dried cherries.  Bring to a boil, then reduce the heat and let simmer for about 5 minutes to soften the cherries.  Let stand while you prepare the rest of the filling.  

In a skillet, heat 1 Tbsp olive oil over medium heat and sauté the onion and fennel until soft.  Add the minced garlic and cook for 1 more minute.  Transfer the mixture to a mixing bowl.  Add the thyme, sage, breadcrumbs, 1/4 tsp salt, 1/4 tsp pepper, and melted butter to the mixing bowl.  Drain the cherries, reserving 1/4 cup of the chicken stock they were softened in.  Add that 1/4 cup of reserved stock to the filling mixture and stir to combine.  

Slice horizontally through the center of the pork roast, but do not cut through to the other side.  Lay it flat and cover with a piece of plastic wrap.  Use a meat mallet to pound to about 1/2 inch thickness.  Brush with 1 Tbsp olive oil, then season with salt and pepper.   Spread the filling mixture evenly over the pork.  Roll up, starting with the short side and secure with kitchen twine.  

Heat a large skillet over medium high heat. Add 1 Tbsp olive oil to the pan.  Add the pork and brown on all sides.  Transfer the pork to a roasting pan.  Pour 2 cups of chicken stock into the bottom of the roasting pan.  Roast at 400 degrees for 45-55 minutes, until the center reads 140 degrees.  Remove from the oven and let rest while you prepare the glaze.

For the glaze

Combine all ingredients in a small saucepan over medium heat.  Bring to a boil, stirring frequently.  Let cook at a boil, continuing to stir, until the sauce thickens, about 5-8 minutes.  

To serve

Slice the pork into about 1 1/2 inch thick slices.  Spoon the balsamic cherry glaze over the top.