For the kale pesto: Put the kale leaves in the blender. Put the nuts in a skillet over medium heat and cook, shaking the pan every so often, until brown and toasty. Put the toasted nuts, cheese, garlic, lemon zest, 1 tablespoon lemon juice and 1/4 teaspoon salt in the blender. Puree; slowly drizzle oil into the mixture until it is as smooth as you like it. Season to taste.
For the tomato jam: Simmer the brown sugar, vinegar, honey, tomatoes and shallot in a pan over medium-low heat until it becomes jam-like, 20 to 30 minutes. Puree, if desired; keep warm.
For the cod: Meanwhile, preheat the oven to 450 degrees F. Rub 1 tablespoon of pesto onto each fillet, reserving about 2 tablespoons pesto. Place the cod on a foil-lined baking sheet and roast until opaque throughout, 12 to 15 minutes for frozen cod or 10 minutes for fresh.
Top fillets with the reserved pesto and dollops of tomato jam.
If using frozen fish then be sure to rinse the pieces under cold water to get rid of the ice glaze, then pat them dry with a paper towel before cooking.