Prepare the salmon: Pat the salmon fillet completely dry with paper towels. Ensure all pin bones are removed using tweezers or pliers. The drier the salmon, the better the cure will penetrate.

Make the cure: In a medium bowl, combine the kosher salt, granulated sugar, freshly ground black pepper, chopped fresh dill, and grated beets. Mix well until everything is evenly distributed. If using, stir in the aquavit or vodka.

Cure the salmon: Lay a large piece of plastic wrap, about 3 feet long, on your counter. Spread about half of the cure mixture onto the plastic wrap in a rectangle slightly larger than your salmon fillet. Place the salmon fillet, skin-side down, on top of the cure. Evenly cover the flesh-side of the salmon with the remaining cure mixture.

Wrap and weigh: Tightly wrap the salmon in several layers of plastic wrap to ensure it's fully sealed. Place the wrapped salmon in a shallow dish or baking pan (this will catch any liquid released during curing). Place a heavy object (such as a few cans or a brick) on top of the salmon to press it.

Refrigerate and flip: Refrigerate for 2 to 3 days. Flip the salmon once every 12 hours and pour off any accumulated liquid from the dish. The longer it cures, the firmer and saltier the gravlax will become.

Serve: After curing, unwrap the salmon. Scrape off all the cure mixture, dill, and beets. Pat the salmon dry with paper towels. Place the salmon skin-side down on a cutting board. Using a very sharp knife, slice the gravlax thinly on an angle, away from the skin. Serve immediately or store any leftover gravlax tightly wrapped in the refrigerator for up to 5 days.