Using a spice grinder or a mortar and pestle, grind the pieces of bay leaf and the peppercorns until finely ground. Transfer to a small bowl and add the salt, brown sugar and garlic powder, and stir to combine.
3 whole dried bay leaves, 1 tsp black peppercorns, 1 tsp fine salt, 1 Tbsp dark brown sugar, 1 1/2 tsp garlic powder
Cut 2-3 deep slashes crosswise into the thicker end of each chicken breast (don't cut all the way through!) so they're a more even thickness all the way across. Place the chicken on a large plate and sprinkle generously all over with the spice/salt mixture. Drag the chicken around on the plate a bit, to get all the rub onto it. Refrigerate, uncovered, for at least 30 minutes and up to 1 hour (if you go less than half an hour, the brining process won’t be done; much longer than an hour and you'll alter the texture of the chicken so it's unpleasant to eat).
2 skinless chicken breasts
When you're ready to cook, preheat the oven to Combi Steam, 430°F/220°C, 60% (high) steam. Take the chicken out of the fridge. Pat it all over with paper towel to remove any moisture and excess brine mixture (you don't have to rub off all the brine, just any large clumps or loose bits).
Rub the chicken with the olive oil and place it onto a lined sheet pan or baking dish. Roast in the preheated oven until cooked through but juicy, approximately 14 minutes. If you have a meat probe and would like to use that, the internal temperature at the thickest part of the chicken should reach 155°F/68°C.
2 Tbsp olive oil
Let the cooked chicken rest for 7-10 minutes in a warm place - don't skip this as it finished the cooking process, and makes a huge difference to the texture and juiciness. The meat should reach an internal temperature of 165°F/73°C during resting. If you don't have a probe, check for doneness by cutting into the chicken - it should be white and juicy and no longer pink.
Slice the chicken crosswise (against the grain) and serve warm or cold.