My sister brought this to me based on something she had in a restaurant, and was sure I could duplicate it. Well, I did a little research (early 80's - no internet), and found a couple of things. So we worked together and this is what we came up with. Oh, and I've updated it to make it simpler for modern day shoppers - we no longer have to wash fresh spinach! So here goes a truly original recipe, that only my family has known about...until now.
1Cook bacon pieces in a medium sauce pan over medium heat till crispy. With a slotted spoon remove all the bacon pieces to a paper towel, to drain. Turn off heat and allow to slightly cool. Sieve egg yolks into bacon fat, add red wine vinegar, lemon juice, and seasonings. This is where you can get creative; taste dressing, if it's too tart for you add more lemon juice, if you like it more tart add more red wine vinegar.
2Meanwhile, assemble spinach, mushrooms, scallions, chopped egg whites, and bacon bits, toss lightly. Serve with the warm bacon dressing, allowing guests to pour their own amount of dressing.
3Note: this pairs well with my Manicotti or Fettuccine recipes. Pass the garlic bread and wine!