Pan size is important. It shouldn't be too small or too large. The size should be just enough so that your tofu will be laid out in two layers filling the most of the pan space. For two blocks, we used 12" pan. (For one block, 8" is probably good. If you are making more than 2 blocks of tofu, you probably want to do it in batches. If you are making more than 2 blocks, do it in batches for best result.)
Slice onion into 1/4" thickness. If you cut it too thin, the texture and flavor won't be as good. 2/3 Onion, Medium
Mix all seasoning ingredients. 8 TBS Soy Sauce, 5 tsp Gochugaru, Coarse Grind, 1.5 tsp Sugar, 1 tsp Mulyeot (Korean Corn Syrup), 1 TBS Sesame Oil, 3 TBS Garlic, 4 Green Onion , 1/8 tsp Black Pepper, 2 tsp Sesame Seeds
Rinse firm tofu under running water and pat-dry well. The drier it is, the better it will be. 2 Package Firm Tofu
Cut tofu in half and slice into 1/2" thickness. Pat-dry any moisture.
Pre-heat a pan on medium heat well. Add about 2 TB of oil. When the oil forms waves, it's preheated.
Pan-fry the half the tofu slices. Flip when it's golden and cook the other side until golden.
Remove pan-fried tofu from the pan. Add another 2 TB of oil and cook the rest of the tofu until both sides are golden.
Add seasoning about 2 tsp per tofu slice. Then add second layer of tofu on top. Then add seasoning on top.
Add onion slices on top.
Add rest of the seasoning around the edge of the pan.
Add water around the edges of the pan (not directly on the tofu). Water amount may vary depending on how much you cook and how wide the pan is. In general you want water to fill the bottom of the pan with 1/2" depth. 4 TBS Water
Close the lid and let it come to boil on high heat until it starts to boil. (about 2 min).
AS SOON AS it starts to boil, turn the heat down to low (about 2 out of 10 for us). Use a spoon to scoop seasoning from the side of the pan and pour all over the top layer of tofu. You might wanna til the pan to scoop the seasoning.
Then close the lid and let it cook for about 3 min. Once again scoop the seasoning from the side and pour all over the top layer.
Let it cook covered for another 3 min then repeat the pouring of the seasoning one more time.
Let it cook covered for another 2-3 min until there is a small amount of liquid is left at the bottom of the pan.
Remove from heat and serve immediately.
Depending on the amount and type of tofu, pan size etc, you may have to adjust water amount or cooking time. It may take a few times to get the feel for it. If it still tastes bland at the end, try sprinkling some salt and pepper before serving.