Slice tofu into appropriate thickness and size, then pat dry with a kitchen towel.

Slice onion thinly, chop green onion, and slice chili pepper. Prepare them for cooking.

Mix red pepper flakes, soy sauce, minced garlic, water, sesame oil, and sesame seeds to create the sauce. Add green onion and chili pepper to the mixture.

Heat oil in a pan and sauté onion until translucent and golden. Remove and set aside.

In the same pan, add oil and fry tofu until golden brown on both sides.

Pour the prepared sauce over the tofu and simmer, flipping occasionally, until the tofu absorbs the flavors.