Instead of seafood, gravlax is made with butternut squash (or carrots) for a vegetarian take on Danish smørrebrød (an open-faced sandwich). The beauty of smørrebrød is that you personalize it to your tastes, so the options are virtually endless.
Smoked salmon or pickled herring take this sandwich to another level, adding even more Scandinavian flair.
Per serving:
For gravlax, using a speed peeler or mandolin, shave squash or carrots into very thin ribbons (almost see-through); add to a large bowl. Heat vinegar, maple syrup, water, caraway, and salt over medium heat until beginning to bubble around edges. Immediately pour over squash or carrots, and toss to combine. Cover and rest at room temperature for at least 4 hours. You can also make ahead and store airtight in refrigerator up to 2 weeks.
To assemble, toast bread, if you wish. Spread with mustard, and assemble sandwiches with sliced eggs, cucumber slices, gravlax, and sprouts. Drizzle with olive oil and dust with smoked paprika. Serve.