Pork with Squash and Apples

1 tsp nutmeg
1 1/2 tsp minced garlic (about 2 large cloves)
1 tsp dried sage
2 lbs pork tenderloin (trimmed)
Kosher salt and freshly ground pepper
1 small butternut squash, peeled and cut into 1" chunks
2 Granny Smith apples, peeled and cut into 1/2" pieces
1 medium red onion, cut into 1/2" pieces
1 Tbsp honey mustard
1 sprig fresh rosemary
5 Tbsp butter, cut into pieces

Preheat oven to 425 degrees.  Mix the nutmeg, 1 tsp garlic, and sage in a bowl.  Rub over the pork and season with salt and pepper.

Toss the squash, apples, onion and remaining 1/2 tsp garlic, the honey mustard, and salt and pepper to taste in a bowl.  Spread out on a long sheet of foil.  Add the rosemary and 3 Tbsp butter, then bring the ends of the foil together and crimp to seal into a packet.  Place the packet on a baking sheet and roast on the upper rack until tender, 30 - 35 minutes.  Poke holes in the packet to release steam.

Meanwhile, heat a large ovenproof skillet over medium-high heat.  Add the remaining 2 Tbsp butter, then brown the pork on all sides, about 8 minutes.  Add 2 Tbsp water and scrape up any browned bits from the pan, then transfer the skillet to the lower oven rack and roast until a thermometer registers 150 degrees, about 15 minutes.  Transfer the meat to a cutting board and let rest 5 minutes.

Return the skillet to medium heat.  Add 1/2 cup water, scrape up any browned bits and simmer about 2 minutes.  Slice the pork and drizzle with pan juices.  Serve with the squash and apples.