Rosemary-Prime-Dijon-Rib
-Ingredients: 2 white onions, cut to 1-inch (2.5 cm) slice ¼ c Dijon mustard 1 prime rib (about 6 lbs/2.7 kg) 1 1/2 cups (375 ml) kosher salt ⅓ c ( 75 mL ) prepared horseradish 2 tbsp. 2 tbsp (30 ml) mustard seeds 2 tbsp. 2 tbsp (30 ml) fresh thyme 2 tbsp. 2…