Put the butter in a pan over medium heat and let it melt. Add the water and then put in the Swiss chard along with a dash of salt. Place a lid on the pan for 1-2 minutes to let the Swiss chard steam, stirring occasionally. Remove the Swiss chard with tongs and set aside when it is almost cooked through.
Place a small amount of the Swiss chard at the bottom of each of four 10-ounce ramekins. Place a layer of tomatoes and prosciutto on top, then add a layer of the manchego cheese (the ramekin should only be approximately 1/3 full). Place another layer of Swiss chard, tomato, manchego, and prosciutto. Crack 2 eggs on top of each ramekin and then sprinkle the panko and more machego cheese on the top.
Cook for 5-8 minutes, depending on how done you like your eggs. Serve immediately.