Step 1: Preheat your oven to 375°F (190°C). Pat the wild turkey breast completely dry with paper towels. Season generously all over with salt, black pepper, garlic powder, and paprika.
Step 2: Heat the olive oil and butter in a large, oven-safe skillet (cast iron works wonderfully) over medium-high heat. Once the butter is melted and sizzling, carefully place the seasoned turkey breast in the hot skillet.
Step 3: Sear the turkey breast for 4-5 minutes per side, until a deep golden-brown crust forms.
Step 4: Once seared on both sides, transfer the skillet to the preheated oven. Roast for 15-25 minutes, or until an instant-read thermometer inserted into the thickest part of the breast registers 160°F (71°C).
Step 5: Remove the skillet from the oven and transfer the turkey breast to a cutting board. Tent it loosely with foil and let it rest for at least 10 minutes.
Step 6: While the turkey rests, return the skillet to the stovetop over medium heat. Add the minced shallot (or onion) and cook for 2-3 minutes until softened and fragrant, scraping up any browned bits from the bottom of the pan.
Step 7: Add the sliced mushrooms to the skillet. Cook, stirring occasionally, for 5-7 minutes until they have released their moisture and are nicely browned.
Step 8: Stir in the minced garlic and cook for another minute until fragrant.
Step 9: Pour in the chicken broth and bring it to a simmer, scraping any remaining flavorful bits from the bottom of the pan. Let it reduce slightly for 2-3 minutes.
Step 10: Reduce the heat to low and stir in the heavy cream and Dijon mustard. Simmer gently for 3-5 minutes, or until the sauce has thickened to your desired consistency. Taste and adjust seasoning with salt and pepper as needed.
Step 11: Slice the rested wild turkey breast against the grain into 1/2-inch thick medallions. Arrange the slices on serving plates and spoon the creamy mushroom sauce generously over the top. Garnish with fresh parsley, if desired. Serve immediately.