In a large bowl, throw in the steak, soy sauce, calamansi juice, and black pepper. Mix all the ingredients together, then let it sit for at least 30 minutes to marinade (or overnight).
Take two large onions, peel the skin off, and slice them into thick rings.
Plug in your instant pot, and press Saute and keep it on Normal mode. Allow it to heat up for a few minutes, then pour in oil and sautee the onion rings until translucent.
Heat up oil and fry marinated meat for 3-5 minutes.
Dump in the meat and the marinade inside the instant pot. Add a pinch of salt to taste, stir it up, and put the Instant Pot lid on. Make sure that the vent is pointed towards Sealing.
Press cancel to turn off the Saute mode, and press Pressure Cook, keeping it on Normal. Make sure your pressure level is on High Pressure, and then set the time for 7 minutes.
After the 7 minutes, use oven mitts or a long spatula to release the pressure from the vent. After all the pressure has been released, you can open the lid safely.
Press Cancel and Saute mode to let it simmer while you taste the sauce. Add the sugar and more salt if needed to taste.
Turn off the Instant Pot, and serve your bistek with a side of white rice!
