Preheat a sauté pan on medium heat and coat with 1-2 tbsp of cooking oil.
Carefully press out excess liquid from tofu and pat dry in wet areas. Slice into ¼ inch thick squares. Season lightly with a bit of salt & pepper on each side.
Once pan is heated, place tofu and allow it to cook on each side until it turns light golden brown. You don't need to make the tofu crispy, just enough to give it some color.
When tofu is golden brown on each side, temporarily remove from the pan. Then, sauté onions and garlic until fragrant, or when onions start sweat. Add the tofu back into pan and stir.
Lower down the heat to medium low and allow the ingredients to sit in the pan as it cools in temperature. Then, gradually add half of the sauce with the ingredients. stir and make sure tofu are in a single layer to absorb the liquids. Leave it alone to simmer for about 4-6 minutes or until liquids have slightly reduced.
Once liquids have slightly reduced, set your stove to low. Add the remaining sauce. And let it sit until tofu absorbs majority of the color from the sauce or liquid has reduced majority of the amount. This should take between 5-10 minutes depending on your stove top. Occasionally stir in between. Place a lid on top of the pan as it simmers. Turn off heat once majority of the liquids have been absorbed. Toss in green onions and garnish with sesame seeds. Best served with a side of kimchi and rice. ¾