Quick, easy, & delicious Pork Bulgogi in 20 minutes!

Ingredients in order of addition: 1-2 tbsp cooking oil (vegetable, soy, canola, or other) 3-6 garlic cloves, grated or minced 1-2 tbsps worth ginger, grated or minced 1.5 lbs pork shoulder, sliced thin 3 tsp soy sauce 1.5 tbsp brown sugar 2-3 tbsp gochujang 1 medium onion, sliced 4 green onions, sliced 1 tbsp sesame oil Optional: toasted sesame seeds