Trim the pork tenderloins of silver skin and excess fat, then butterfly or filet them and roll out to about 1/4-inch thickness.

Steam or wilt the spinach until softened, then drain well and squeeze out excess moisture; set aside.

In a skillet, melt the butter over medium heat and add the minced garlic; cook until fragrant and beginning to brown.

Add the sliced mushrooms to the pan; cook until they release their liquids and begin to brown.

Add the wilted spinach to the mushrooms, sauté until the pan liquids evaporate, then remove from heat and allow the mixture to cool.

Spread the cooled spinach-mushroom mixture evenly over each butterflied tenderloin.

Top the mixture with crumbled feta, chopped fresh oregano, and salt and pepper to taste.

Roll each tenderloin tightly to enclose the filling and wrap the outside with bacon strips to secure the roll.

Cook the bacon-wrapped rolls until the internal temperature of the pork reaches 175°F (79°C). If smoking (Traeger), smoke for about 3 hours and increase heat at the end to finish; alternatively roast in a 375°F oven or cook over indirect grill heat.

Remove from heat and let the tenderloins rest for 10 minutes, then slice into 1 to 1 1/2-inch rounds to serve.