1. In a small bowl, stir together the mayo, sour cream, horseradish, and marjoram; let stand for about 10 minutes at room temperature to allow the flavors to blend (alternatively, cover and refrigerate for up to 6 hours, if refrigerating, return to room temperature before using). 2. Preheat sandwich grill. 3. Place the bread slices, cut sides down, on a work surface and spread 1 side of each bread slice with the butter. 4. Turn and spread the unbuttered sides of the bread with the mayonnaise mixture. 5. On each of 2 bread slices, mayo sides up, arrange half of the roast beef. 6. Season liberally with salt and pepper. 7. Divide the cheese and watercress on top. 8. Cover with the remaining 2 bread slices, mayo sides down, and press gently to pack. 9. Place the panini in the grill, close the top plate, and cook until the bread is golden and toasted, the meat is warmed through, and the watercress is nearly wilted, 3-5 minutes. 10. Cut each sandwich in half on the diagonal and serve right away. ---------------------------------------------------------------------------
Nutrition
Ingredients
