In a small, heavy saucepan, bring the coffee,
vinegar, and maple syrup to a boil. Lower the
heat, and simmer
until the mixture turns syrupy, 10 to 12
minutes. Remove from the heat and stir in the
lemon juice and cardamom. Whisk in the butter,
cover, and keep warm.
Heat the oil in a large nonstick skillet over
medium-high heat until hot but not smoking.
Season the salmon with salt, and add to the
skillet skin side down. Cook, undisturbed,
until deeply golden, 3 to 4 minutes. Turn and
cook until just barely cooked through, 2 to 4
Divide the salmon among serving plates, and
drizzle with the sauce.