I love these, I make them from memory - here is my attempt at writing this down and giving you quantities.
- 2 (340.19-453.59 g) beef tenderloin steaks or 2 (340.19-453.59 g) filet of beef
- 2.46 ml salt or 1.23 ml kosher salt
- 2.46 ml freshly ground coarse black pepper
- 29.58 ml canola oil
- 29.58 ml butter or 29.58 ml margarine
- 1 small yellow onion, sliced and separated into rings
- 1 small red onion, sliced and separated into rings
- 1 bunch green onion, chopped
- 6 shallots, chopped
- 226.79 g button mushrooms, sliced
- 2 garlic cloves, minced
- 118.29 ml cognac or 118.29 ml red wine or 118.29 ml low sodium beef broth
- 59.14 ml low sodium beef broth
- salt, to taste
- fresh ground black pepper, to taste
- chopped fresh parsley, garnish (optional)
- Sprinkle beef evenly with 1/2 teaspoon salt or 1/4 teaspoon kosher salt and 1/2 teaspoon pepper.
- Brown filets in 1 tablespoon hot oil in an ovenproof or cast-iron skillet over medium-high heat 3 minutes on each side.
- Remove filets, reserving drippings in skillet.
- Melt 2 teablespoons butter in drippings over medium-high heat.
- Add yellow and red onion rings, and saute 5 minutes.
- Add green onions, shallots, mushrooms and garlic.(If more oil is needed add remaining tablespoon), saute 15 minutes or until lightly browned.
- Stir in cognac and broth; cook over medium-high heat, stirring constantly, until liquid evaporates(about 5 minutes).
- Place filets on top of onion mixture in skillet.
- Cover with aluminum foil.
- Bake at 400F for 15-20 minutes or until thermometer inserted in thickest portion of meat register 135F(medium rare).
- Remove filets from skillet, reserving onion mixture in skillet, cover filets loosely, and let stand at room temperature 10 minute.
- Cook onion mixture over medium heat, stirring constantly; 5 min or until liquid evaporates.
- Add salt and pepper to taste, if needed.
- Serve with filets.