1. Peel and finely chop the shallots.
2. In a saucepan, melt the butter over low heat, add the shallots.
3. Cover the saucepan, let cook and reduce for about ten minutes (the shallots should be tender).
4. Then, deglaze with Cognac and red wine.
5. Let it reduce to the maximum, stirring regularly during cooking.
6. Add the brown sauce base (available in jars in supermarkets) and reduce to desired consistency.
7. Season with salt and pepper.
8. Meanwhile, after slicing the steak into 6 pieces, cook the pieces in very hot oil to the desired degree of doneness.
9. When the steaks are cooked, season with salt and pepper, then pour the sauce over them and serve hot.
10. As a side dish: french fries, dauphine potatoes, or croquettes.