Once the crust comes out of the oven, let cool for 5 minutes. Scrape the date mixture over the crust and gently spread it evenly over the bottom.

Bake packets until fish is opaque at the center, 14–16 minutes. Halibut and thicker black cod fillets will take closer to 20 minutes. Reserve packet of fish without compote for tomorrow’s lunch.

Meanwhile, make the filling . Stir together date paste, oil, and 1/2 tablespoon water in a small bowl until liquid is absorbed. (It will be slightly sticky but able to be shaped into a ball.) ...