In a large sauté pan on medium-low heat, add 2 tablespoons of oil. Once heated, add the bell peppers with a pinch of salt.
Cook slowly, stirring occasionally, until the peppers are softened and lightly caramelized (about 15-20 minutes). Set them aside off the heat.
While the peppers are cooking: dice the celery and smash the garlic (this forms the mirepoix).
In a sauce pot, add 1 tablespoon of olive or grapeseed oil and sauté the mirepoix until fragrant or lightly golden brown. Add a pinch of salt and black pepper.
Add the bay leaf and sage along with 2 quarts of chicken stock, and bring it up to a boil, then gently simmer for 30 minutes. (This process, called fortifying your stock, adds depth of flavor. Feel free to add mushrooms, herbs, alliums, or dry spices during fortification if desired!).
Once the stock has simmered for 30 minutes or reduced by half, strain through a mesh strainer and return it to the pot. Add the caramelized bell peppers.
Once the turkey is resting and you have the cooking liquid strained, add the strained cooking liquid to your fortified stock and bring it up to a boil.
Now, it’s time to thicken the sauce: In a separate small bowl, whisk 1 tablespoon of cornstarch with a little water until a thick paste forms. Whisk that into your hot gravy until the desired thickness is achieved! Repeat as needed until the gravy reaches the proper consistency. (Do this little by little to avoid over-thickening the sauce).
Season to taste with Balinese Truffle Salt and ground black pepper.