@leejayd I hardly make a classic vinaigrette anymore, which is what you made but with added garlic and capers. And, well, it's very unusual to hear someone use it on steak instead of on a salad.
However, here's a delicious alternative with thousands of possible variations, that can be used on nearly everything.
It's known as a "vinaigrette salée" in classic French cuisine. It is so simple to make! You need a good mayonnaise as a base, preferably homemade!
Basic sauce; I usually take 3 large heaped tbsp. of mayo. Add 1 tbsp. of white vinegar (I mostly use homemade tarragon vinegar). Add 2 tbsp. of cold water. Extra s&p to taste. You need a whisk to beat all of this into a perfect smooth stable sauce.
It all depends how thin you want your sauce. This one is quite thin but you can use less water if you want the sauce somewhat thicker. As you can guess, all kinds of additions are possible, such as adding extra mustard, capers and garlic as you did etc. Spices or fresh herbs etc. etc. Your only limit is your imagination.
Oh, and by the way; everyone loves this sauce.... while many people hate vinaigrettes. How about adding fresh chopped tarragon, parsley, garlic and a pinch of cayenne to your next steak dressing made with this sauce base?
Here's an example of vinaigrette salée that went well with chicken with a chunk of pine apple, salmon, shrimp, veal, couscous salad... all on just one plate.