Slice the onion and cut the green onion into finger-length pieces, then split them in half.

Prepare the cornstarch slurry by mixing 1 tbsp cornstarch with 2 tbsp water.

Mix the seasoning ingredients: 2 tbsp gochujang, 2 tbsp chili powder, 1 tbsp minced garlic, 1 tbsp sugar, and 6 tbsp soy sauce.

Add 1/2 cup water to a pot and bring to a boil. Once boiling, add the soybean sprouts and vegetables.

Add the prepared seasoning mixture and stir well to coat the ingredients evenly.

Pour in the cornstarch slurry and stir until the sauce thickens.