Instant pot Mongolian Beef

Name: Instant pot Mongolian Beef
Ingredients: 1-1.5 pounds flank steak (sliced across the grains); 1 tablespoon cornstarch; 1 tablespoons extra virgin olive oil; 1/2 cup brown sugar (or 2/3 cups for those with a sweet tooth); 10 cloves garlic (minced); 1 tablespoon fresh ginger (minced); 1/2 cup lite soy sauce; 1 cup water; 1 tablespoon rice vinegar; 1 teaspoon red pepper flakes (optional); 2 tablespoons cornstarch; 1/2 cup water; 1/4 cup green onions (chopped); 1 teaspoon sesame seeds; Hot chilli oil paste