Hazırlanışı
1Preheat the oven to 350 degrees F (175 degrees C).
2Melt butter in an oven-proof skillet over medium heat. Sear tenderloin in melted butter, then transfer to a plate.
3Add onions to the skillet; cook and stir for 2 to 3 minutes. Stir in apple and cook until golden brown. Stir in flour and cook for about 30 seconds.