Place a small saucepan over medium heat.
Combine the red wine, the beef broth, the brandy, the red wine vinegar, the thyme leaves, the lemon zest, and the lemon juice in the pan. Bring to a boil, reduce the heat, and keep at a rolling simmer until reduced to 1/4 cup, about 12 minutes.
Hold the sauce warm until you're ready to serve.
Combine the peppercorns, sugar, and salt on a small plate or shallow dish. Set aside.
In another mixing bowl, whip the egg white to a stable froth, but not quite to stiff peaks.
Pat the swordfish steaks dry with paper towels. Now, brush on all sides with the egg white. Set the steaks on a wire rack (or a plate) for a few moments to allow the egg white to get slightly tacky.
Heat a grill or grill pan to medium-high heat.
Spray a clean grill rag with cooking spray and evenly wipe the grill grates until clean and evenly glistening.
Press the fish into the peppercorn mixture on one side of each fillet.
Place the steaks peppercorn-side down onto the grill. Cook for 5 minutes without moving.
Using a fish spatula, turn the fish and finish cooking through, about 3 minutes. Transfer to a plate to rest.
Using a spoon, swirl the softened butter into the sauce.
Serve, spooning the sauce over the fish fillets.