Vegan "Bulgogi" Korean BBQ Beef (gluten-free, refined sugar free, oil free option)

Name: Vegan "Bulgogi" Korean BBQ Beef (gluten-free, refined sugar free, oil free option)
Prep time: 10 min
Cook time: 20 min
Total time: 30 min
Cuisine: Korean, Asian
Ingredients: 1-2 cups soy curls, rehydrated*; 2 cups shiitake mushrooms, roughly chopped or pulsed in food processor until chunky; 1/2 small onion, thinly sliced; 1/2 cup gluten-free soy sauce; 1/4 cup coconut sugar; 1 tbsp rice vinegar; 1/2 tsp sesame oil; 1/2 tsp black pepper; 2 tsp fresh ginger, grated; 4 cloves of garlic, minced; 1 tbsp red pepper flakes; 3 scallions, thinly sliced; 1 tbsp arrowroot powder (or sub cornstarch); water; scallions; additional sesame seeds