If necessary, defrost the salmon fillet, then season with salt, pepper and possibly a little lemon juice. Heat some oil in a pan and fry the salmon in it. Chop the onions and add them.
When the salmon is almost done, add the quartered tomatoes and the cream. Likewise the crumbled cheese. Let it steep a little, season well with salt and pepper.
Arrange on a plate and sprinkle with basil. Noodles or rice go well with this.