Heat the oven to 400°F.

• Pat the trout fillets dry with a paper towel. Cut them in half crosswise. Season generously with salt and pepper.
• Peel and thinly slice the shallot.
• Zest the lemon. Cut half into 4 thin slices; juice the remaining half.

Lay the parchment paper sheets side by side. Divide the spinach and shallots between the 2 sheets and season with salt and pepper. Top with the trout pieces and lemon slices. Dot each with 1 tablespoon butter (or 2 teaspoons oil).
Working with 1 sheet at a time, bring 2 opposite sides of the parchment to the center and fold them together several times to create a tight seam. Fold up each end several times to form a tight seal.

Place the packets on a sheet pan, sealed sides up, and bake until the parchment is puffed and browned and the trout is tender when pierced with a skewer or sharp knife, 12 to 15 minutes. While the trout cooks, make the date and apricot salad.

• Coarsely chop the dried apricots.
• Thinly slice the dates.
• Coarsely chop the almonds.
• Strip the parsley leaves from the stems; coarsely chop the leaves.

In a pan over medium heat, heat 1 tablespoon olive oil until hot but not smoking. Add the apricots, almonds, and dates and cook just until warmed through, 2 to 3 minutes. Remove from the heat. Add the lemon zest and juice, the parsley, and sumac; toss to coat. Season to taste with salt and pepper, if needed.

Open the trout packets, careful of any venting steam. Transfer the packets to individual plates. Spoon the date and apricot salad alongside and serve.