Wet Brine for Moist Turkey: Depending on the size of your turkey breast, mix 90g (3.17oz) salt with 1500ml (6 cups) of cold running water or 120g (4.23oz) salt with 2000ml (8 cups) cold running water in a large mixing bowl. Ensure the salt has fully dissolved. Fully submerge the turkey breast in the salted-water and place it in the fridge for at least 4 to 8 hours. *Pro Tip: Brining turkey breast for over 8 hours may result in ham-like meat texture.
Prepare Pressure Cooker: Heat up your pressure cooker (Instant Pot: press Sauté button and click Adjust button to Sauté More function). Make sure your pot is as hot as it can be (Instant Pot: wait until indicator says HOT).
Sauté Onion and Garlic: Add 1 tablespoon (15ml) olive oil. Then, add diced onion in the pressure cooker. Sauté for roughly 2 minutes until soften. Add minced garlic and sauté for another 30 seconds until fragrant. Season with kosher salt and ground black pepper.
Sauté Celery and Carrot: Add in chopped celery and carrot. Sauté until the vegetables are slightly browned (roughly 5 – 7 minutes).
Deglaze: Add a dash of sherry wine in the pressure cooker and deglaze by scrubbing the flavorful brown bits off the bottom of the pot with a wooden spoon.
Add Turkey Breast: Add 1 cup (250ml) unsalted chicken stock, 2 bay leaves, a pinch of dried rosemary, a pinch of dried thyme and a pinch of dried sage (rub the herbs with your fingers to “activate” them) in the Instant Pot. Give it a quick stir and carefully place the turkey breast in the pressure cooker.
Optional - Add Pot-in-Pot Potatoes (If you're making mashed potatoes): Place a stainless steel bowl on top of the turkey breast and add in halved Yukon gold potatoes.
Pressure Cook Turkey Breast: Close lid and pressure cook at High Pressure for 28 – 34 minutes, then 15 minutes Natural Release (after 15 minutes of natural release, turn the Venting Knob to Venting Position to release the remaining pressure). Open the lid carefully.
Make Mashed Potatoes: Remove the stainless steel bowl and place all the potatoes in a large mixing bowl. Mash the potatoes with a fork or masher. Add 1 – 2 tbsp (14g – 28g) unsalted butter, 30g grated Parmesan cheese, and 100ml milk or cream. Continue mashing and mixing until desired consistency. Season with kosher salt and ground black pepper to taste. For creamier mashed potatoes, use more milk/cream.
Check Turkey Breast Temperature: Use a meat thermometer to ensure the thickest part of the turkey breast registers over 161°F (72°C). Set aside on a chopping board to rest for 15 minutes. The carryover heat will continue to cook the turkey to 165°F (74°C)
Make Turkey Gravy: Heat the pressure cooker over medium heat (Instant Pot: Press Saute button). Mix 2 ½ tbsp cornstarch with 3 tbsp cold water and stir the mixture into the turkey gravy one third at a time until desired thickness. Taste the sauce and season with salt and ground black pepper if necessary.
Optional - Brown Turkey Breast Skin: Pat dry the turkey breast skin with paper towels. Mix 1 tbsp honey with 1 ½ tbsp regular soy sauce and apply onto the turkey breast skin. Use a blowtorch or place turkey breast under broiler for a few minutes to brown the skin.
Serve: Slice the turkey breast thinly on an angle. Drizzle turkey gravy over the turkey breast & mashed potatoes. Serve immediately.