Step 1

Cut fish (or ask your fishmonger to slice it) into single serving fillets no thicker than 1/2 inch - 1/4 inch thickness is optimal. For irregularly sized cuts like cod, you may need to slice some fillets in half lengthwise to make them thinner. Alternatively, you can slice the fish into smaller bite-sized fish sticks, about 2 inches long and 1 inch wide (the smaller pieces will be a bit easier to manage in the frying pan).

Step 2

In a mixing bowl, whisk together the seltzer, flour, cornstarch, salt, garlic powder, and cayenne to make a batter. The batter will bubble at first, then settle. Stir together the panko breadcrumbs and sesame seeds, then pour them onto a plate. Have an empty plate handy for the breaded fish.

Step 3

Dip each piece of fish into the batter. When you pull the fish out of the batter, let the excess batter run back into the bowl.

Step 4

After dipping in the batter, gently roll each piece in panko crumbs to coat. Leaving too much batter on the fish will lead to clumping and will make the coating fall off the fish when frying, so make sure your fish is only lightly coated with batter before breading. Place the breaded fish onto the empty plate.

Step 5

Heat ½ inch of vegetable oil in a skillet over medium till hot but not smoking. Fry the breaded fish pieces in batches of 3 (if using smaller sized fish sticks, you can fry up to 6 at a time). If the oil is at the correct temperature, it should bubble and sizzle evenly—no splatters or popping. Flip the fish when they turn dark golden brown. Don't flip them till they're completely golden-- the more you flip them, the more fragile the coating will become, so try to only flip each fillet once. If your oil is at the right temperature, it should take about 4-5 minutes per side for the fish to become golden and crisp.

Step 6

Place fried fish pieces on a wire rack to drain, if you have one. This will keep the fish as crisp as possible. Use paper towels to catch the oil drips underneath the rack. If you don’t have a wire rack, you can drain the fish pieces on a double layer of paper towels.Once fish has drained, you make the sauce immediately and serve, or place the wire rack (without paper towels) on a baking sheet in the oven at 200 degrees F for up to 30 minutes till ready to serve. This will keep the fish warm, fresh and crisp.

Step 7

Just before serving, whisk together cornstarch and 2 tbsp water in the bottom of a small saucepan till dissolved. Whisk in orange juice, soy sauce, agave nectar, sesame oil and a pinch of cayenne. Heat the sauce over medium to a simmer for 2-3 minutes, whisking constantly, till it thickens slightly. Remove from heat and let it cool for 2 minutes.Serve fish hot drizzled with the warm orange sesame sauce.