Juicy grilled pork tenderloin is marinated and then grilled. It is finished with a rich beer and mustard sauce.
Combine all ingredients for the marinade and whisk well. Place the two pork tenderloins in a gallon zip top bag and the pour in the marinade. Press out any extra air and seal tightly. Refrigerate for at least an hour, or up to 8 hours.
Preheat your grill to 400 degrees F. Remove the tenderloin from the marinade and shake off any excess shallot or garlic pieces. Reserve the marinade and set aside. Place the tenderloin on the grill.
Grill for 2-3 minutes per side before rotating. Continue cooking and rotating on the grill until the internal temperature of the tenderloin reads 145 degrees F. Remove from the grill and allow to rest for 5-10 minutes.
While the tenderloin is resting, melt the butter in a large skillet over medium high heat. Whisk in the flour and cook until well combined (1-2 minutes). Pour 2 cups of the reserved marinade into the skillet and whisk. Bring the sauce up to a boil and reduce the heat. Allow the sauce to simmer for 3-5 minutes.
Slice the pork tenderloin against the grain into 1/2 inch thick medallions. Top with a spoonful of the beer and mustard glaze before serving.