Place bread in a food processor and plus to make bread crumbs. In a skillet over medium heat, cook bread crumbs in a tablespoon of olive oil until golden brown. Transfer to a bowl and add the horseradish.
Pat pork dry and season with salt and pepper. In a skillet with high heat and 1 tablespoon of olive oil, brown pork on all sides. Move pork to a shallow baking dish.
In a small bowl mix the mustard and mayonnaise. Coat the top and sides of the pork with the mixture. Press the bread crumbs evenly onto the mustard mixture. Make sure there are few free bread crumbs on bottom of the pan as they will blacken when roasting.
Roast for about 30 minutes and check to make sure the crumb topping isn't getting too brown. Tent with tin foil if browning is too quick. Place a meat thermometer in the roast center and cook to 145 degrees for slightly pink or higher to your taste. Transfer pork to cutting board and cut 1/4 inch slices.