Step 1

Heat butter and oil in a large skillet over medium-high heat until butter melts. Add pork, fat side down, and sear until brown, 3-4 minutes. Brown pork on all sides, about 5 minutes more; transfer to a 4- to 6-qt. slow cooker. Add garlic to skillet; cook 30 seconds.

Step 2

Deglaze skillet with wine, scraping up any brown bits. Add milk, cream, porcini, anchovy paste, pepper flakes, and zest; simmer 3 minutes. Pour milk mixture around pork in slow cooker; submerge rosemary and sage. Cover slow cooker and cook pork until an instant-read thermometer inserted into the thickest part register 145 degrees F on low setting, 2 hours. Transfer pork to a platter and tent with foil to keep warm. Discard rosemary and sage.

Step 3

Purée sauce in the slow cooker with a handheld blender until smooth; season with salt and black pepper.

Step 4

Slice pork and serve with sauce and Lemony Polenta.

Step 5

Whisk together the broth, buttermilk, and cornmeal in a saucepan and bring to a boil over medium heat. Reduce heat to low, and cook, whisking constantly, about 5 minutes; remove from heat.

Step 6

Stir in Parmesan, butter, and zest; season with salt and pepper.