Combine the boiling Water (1 fluid ounce), Raw Sugar (1 1/2 tablespoon), Sherry Vinegar (1 fluid ounce), Lemon (2), and Dried Currants (1/4 cup). Let stand for at least 10 minutes.
Heat a small sauce pot over medium heat. Add Olive Oil (1/2 tablespoon) and Brown Mustard Seeds (2 teaspoon). Bloom the seeds in the oil (heat slowly while stirring) until the seeds start to sizzle or pop.
Add Green Apple (1) to the pot. Stir to combine w/ the oil and mustard seed and add the currant mixture and Kosher Salt (to taste). Boil, then reduce to a simmer, and cook for 10-15 min. Add Dijon Mustard (1/2 teaspoon) while hot, and set aside.
Season Trout Fillet (16 ounce) with Kosher Salt (to taste).
Wash Collard Greens (1 bunch) 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 Olive Oil (2 tablespoon). 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 Olive Oil (1 tablespoon). Add Garlic (1 clove). Cook slightly, but do not brown. Add collard greens, and stir as they wilt. Season with Kosher Salt (to taste) and Ground Black Pepper (to taste).
Place a mound of greens in the center of your plate, and top with trout fillet, skin-side up. Spoon mostardo over the trout.