Step 1 In a medium bowl, crush the drained capers with a fork. Whisk in the miso, olive oil, agave and mirin.
Step 2 Slice the salmon filet into 8 pieces and marinate the salmon with the miso-caper mixture in a covered dish or resealable bag for 1 hour in the refrigerator.
Step 3Heat the oven to 425 degrees. Line a rimmed baking sheet with parchment paper. Place the salmon on the baking sheet and bake until the salmon is opaque and flakes easily, 15 to 20 minutes.