Season the whole, gutted sardines with salt and pepper. Toss the seasoned sardines in the flour. Heat a large skillet over medium flame for 2-3 minutes. Add the olive oil. Heat 20-30 seconds. Add the floured sardines to the pan and brown evenly on each side, slowly turning down the flame as you go. Turn off the flame, remove the sardines, and pour off the oil into a can or other safe container.
Place the skillet back on the stove. Turn the flame to medium. Add the shallots and garlic and cook 30-45 seconds, moving them around with a wooden spoon. Add the sardines back to the pan. Add the honey and the rosemary and simmer until the honey reduces. Add the vinegar and again allow it to reduce, about 5 minutes. Toss the sardines to make sure they are evenly coated in the honey and vinegar mixture, about 3-4 minutes. Remove the sardines and allow them to cool a bit. Serve warm or room temperature.