I used a spicy brown mustard and the sauce was absolutely wonderful. I decided to use a programmable thermometer to make sure I didn't overcook the meat and it was a good move since my cook time was slightly faster than what was listed. I'd serve it to friends for sure!
I cook for my two senior parents and I had to cook the meat where there was no noticeable pink, but I think that ruined the meat. My husband & I love medium-rare, but because of my parents we had to sacrifice. The meat ended up being a tad tougher and chewy. Although this happened, the meal was not that bad. Instead of the grainy mustard, I used dijon mustard which didn't have the mustard seeds you see in the picture but was still tastey. I will definitely try this recipe again, but will keep the meat medium-rare.