Combine the Ingredients:

1. In a small saucepan, combine Mama San Mirin, Mama San Sake, soy sauce, granulated sugar, minced garlic, and grated ginger (if using). Stir well to combine.

Simmer and Reduce:

1. Place the saucepan over medium heat and bring the mixture to a simmer. Stir frequently to dissolve the sugar and combine the flavours.
2. Allow the sauce to simmer for about 10-15 minutes, or until it has reduced by about half. This will thicken the sauce and intensify its flavour.

Optional Thickening (If Desired):

1. If you prefer a thicker Teriyaki sauce, mix 1 tablespoon of corn starch with 2 tablespoons of cold water to create a slurry.
2. Slowly pour the slurry into the simmering sauce while stirring continuously.
3. Continue to simmer for an additional 2-3 minutes, or until the sauce reaches your desired thickness. Keep in mind that the sauce will thicken further as it cools.

Cool and Store:

1. Remove the saucepan from heat and let the Teriyaki sauce cool to room temperature. It will thicken a bit more as it cools.
2. Once cooled, transfer the sauce to an airtight container or a glass jar. You can store it in the refrigerator for up to a few weeks.

Use the Teriyaki Sauce:

Your homemade Teriyaki sauce is ready to use! You can use it as a marinade for meat, poultry, or seafood, or as a glaze for grilled or pan-fried dishes.