Preheat your broiler to high heat and, if necessary, move your rack into position.
Halve the peppers long ways. Remove the stems, pith, and seeds.
Coat the peppers with 3 Tbsp of the olive oil. Sprinkle them with salt and pepper, and place them face down on a lined, rimmed cookie sheet.
Broil the peppers until the skins are well charred. Set an initial time on your TimeStick for 10 minutes.
When the alarms sounds, check the peppers. You want them to have lots of char all over, but they needn't be completely black. If not charred yet, reset the timer for a couple minutes and continue broiling.
Place the peppers in a large bowl and cover with plastic wrap. Allow them to sit in their own steam on the countertop for 10 minutes while the skins soften.
Meanwhile, reduce the heat of your oven to 300°F (149°C) and move your rack to the lower third of the oven.
When the peppers have rested, peel their skins off. They should come off with little difficulty. It’s ok if some skin remains on the peppers.
Tear the peppers into ½" wide strips and place in the bottom of an oven-safe casserole or baking dish along with the juices that have accumulated in their resting bowl.
Add the garlic, vinegar, pepper flakes, and, if needed, some salt. Toss to combine.
Nestle the cod in among the peppers with the thin tail section tucked underneath the midsection of the fillet.
Drizzle on 2 Tbsp of the olive oil and season the fillet with salt and pepper.
Probe the thickest part of the fish with a Pro-Series Needle Probe and connect it to your ChefAlarm.
Set the high alarm for 140°F and place the dish in the oven.
While the fish cooks, combine the thinly sliced onions, parsley, capers and the rest of the oil in a bowl. Season with salt.
When the alarm sounds (after about 25-30 minutes), remove the dish from the oven and verify the temperature with your Thermapen ONE.
Allow the fish to rest, then top with the caper and onion mixture.
Garnish with thinly sliced red chili and serve with crusty bread for mopping up the delicious liquid in the bottom of the pan.