Preheat the oven to 325 degrees Fahrenheit.
Cut the Swiss steak to ½ inch thick, preferably along with the grain. Sprinkle it with salt and pepper generously. Dredge the steak with flour, making sure it gets everywhere evenly.
If you have to tenderize the meat, use a tenderizing mallet manually. If you happened to buy it already tenderized, it’s time to sear the meat on high heat for a few short minutes to keep in the moisture.
Take an iron skillet or pan, add some butter or olive oil, and sear each side on high heat for 1-2 minutes.
If you prefer to use butter, it’s best to brown it before adding it to the meat to sear it. Brown butter caramelizes meats, adding so much depth of flavor. Set the slices aside on a plate.
Add the diced onions, garlic, celery, and the remaining butter and olive oil. Glaze them in the fat until they are shiny and slightly soft, over medium-high heat for a few minutes.
Now it’s time to add the tomato paste, smoked paprika, Worcestershire sauce, broth, and sundried tomatoes. Stir them well, and place the meat back into the pan, merging it with the mixture.
Cover a baking pan with foil, and transfer the sauce-covered swiss steak to the pan.
Place it in the middle of the preheated oven, covering it with foil. Bake it for an hour until the meat starts to fall apart.
Serve it with your favorite side dishes.