Put all the ● ingredients in a frying pan and mix well. You can do use 3 tablespoons each of all the ingredients if you like, but we love sesame seeds in our family so I add 5 tablespoons.
You can use konbu seaweed or bonito flake based dashi stock granules, or even use umami seasoning instead. Adding just a little of any of these will increase the mix's umami, but omit it if you prefer.
Start cooking the mixture over medium heat. When it starts to bubble, lower the heat a bit. Keep stirring so that it doesn't burn.
When the moisture has cooked off to almost nothing, turn the heat down very low. Soy sauce burns very easily, so if it starts to smell even a bit nutty, take the pan off the heat immediately.
If the pan is still making popping and sizzling sounds, keep cooking.
If it feels moist when you touch it, it needs a bit more cooking... Take the pan off the heat occasionally, and keep stirring to dry out the mixture.
When the mixture is dry, turn the heat off. If you leave the frying pan on the burner it may keep cooking and get burned, so take the pan off the heat until it cools down.
Keep stirring the mixture around for a little while longer. I think 1 to 2 minutes should do it. Leave it to cool down without covering.
When the mixture has cooled down, mix the sugar in. If you add the sugar when the pan is still hot it will melt, so be sure to let the pan and mixture cool first!
When the sugar is evenly distributed, transfer the mixture to a container with a lid or a jar etc. You could also use the self-closing bag the sesame seeds came in.
The mixture can be stored at room temperature, but if you store it in the refrigerator it's less liable to get moist from the humidity. Shake it up well before use.
Addendum: If you want to grind whole sesame seeds yourself, just grind them half way. There's no need to divide the ground and whole toasted sesame seeds in this case. You can also change the amount of soy sauce and sugar to taste!
Reference recipe: Shira-ae (vegetables with tofu and sesame) can be made with this base mix too. Recipe ID: 2357838
Bell pepper with sesame Recipe ID: 2354583.
Eggplant and shiitake mushrooms with sesame Recipe ID: 2355949.
Although this looks almost the same, this is a namul base Recipe ID: 2357837.
Make an easy sesame salad dressing using this base mix Recipe ID: 2370251.
Story Behind this Recipe
I was able to survive 7 years of making bentos for my children with this mix. Frozen goma-ae (cooked vegetables with sesame sauce) becomes wet by the time it thaws, and the flavors dissipate so it's no good! But making goma-ae for bento every time is a bother and you're likely to have awkward amounts left over. This sesame-sauce base is perfect for families with those kinds of problems.
I'd always made this by eyeballing the ingredients, but I tried measuring things out properly this time. And what do you know - the ratio is quite easy to remember. This mixture is on the sweet side, so please use this as a starting point and adjust the amount of soy sauce and sugar. It has almost no moisture in it, so if you put it in a container with a hermetically sealed lid or a jar with a a screwtop lid, you can even store it at room temperature.