Combine the hot water, raw sugar, sherry vinegar, lemon juice, lemon zest, and dried currants. Let stand for at least 10 minutes.
Heat a small sauce pot over medium heat. Add 1/2 tablespoon olive oil and mustard seeds. Bloom the seeds in the oil (heat slowly while stirring) until the seeds start to sizzle or pop.
Add the apples to the pot. Stir to combine with the oil and mustard seed, then add the currant mixture and salt. Bring to a boil, then reduce to a simmer, and cook for 10-15minutes. Add Dijon mustard while still hot, and set aside.
Season fish with salt to taste. Wash collard greens in water, handling gently so as not to bruise them. Remove stems from collard greens, tear into 2-inch pieces, and set aside.
Heat a sauté pan over medium-high heat. Coat the bottom of the pan with 2 tablespoons olive oil. Continue to heat until the oil begins to lightly smoke. Without overcrowding, add the
fish, skin-side down. Cook without turning or moving until the fish is cooked most of the way through, well colored and crisp on the skin side. Flip, and cook briefly to finish and remove
from pan.
Adjust heat to medium-low, add 1 tablespoon olive oil. Add garlic. Cook slightly, but do not brown. Add collard greens, and stir as they wilt. Season with salt and pepper.
Place a mound of greens in the center of your plate, and top with trout filet, skin-side up.
Spoon mostardo over the trout. Serve and enjoy!
