Defrost spinach in microwave. Wring spinach dry by nesting in kitchen towel and twisting towel over garbage bowl or sink until spinach has given off all of its liquid. Place spinach in a medium mixing bowl. Heat a nonstick skillet over medium heat, add oil and onion and saute the onion until soft, 5 minutes. Add onion to spinach in bowl and return pan to stove top. Turn off heat.
Add remaining ingredients to spinach: bread crumbs, cheese, egg, nutmeg, salt and pepper. Combine mixture with a fork, then form into 3-inch patties. Set aside.
Line bacon up on meat-safe cutting board a few inches apart. Preheat a second skillet over high heat. Reheat the spinach cakes skillet over medium high heat. Season steaks with salt and pepper and set on bacon slices in the center of each slice. Wrap bacon over steaks. Place seam side down in pan and cook 2 minutes on each side. Add 2 tablespoons oil to spinach cakes pan and set cakes in to cook. Work in 2 batches if necessary. Cook cakes 3 minutes on each side.
Reduce heat to medium under steaks after the first 2 minutes on each side. Cook meat another 6 to 10 minutes, turning occasionally, for medium rare to medium well doneness.
Remove meat from the pan and let it rest. Add 1 tablespoon of the butter and flour and cook together 1 minute. Whisk in wine and deglaze pan. Whisk in broth and thicken sauce 1 minute. Add remaining tablespoon butter and remove skillet from heat.
Quarter tomatoes lengthwise.
To serve, set the spinach cakes and steaks beside each other on 2/3 of serving plates and pour sauce evenly over steaks. Scatter a quartered tomato next to spinach cakes on each plate. Drizzle tomatoes with oil, season with salt and pepper and top with chopped chives. Serve plates immediately.