Turn on the Instant pot on manual mode and add oil when it displays 'HOT'.
To the oil, add minced garlic and onion and saute for a couple of mins until the onion starts to get slightly translucent.
Now add the washed and dried rice to the pot and toast the rice for a few minutes while continuously stirring, until the rice gets golden brown and toasty. You will get a nice aroma at this point. Do not walk away at this stage to avoid burning.
Now add the cumin powder, salt, tomato bouillon powder (if using), and saute for a few seconds.
Then add water or stock ( use stock/broth if you didn't use bouillon powder) and stir everything really well to make sure nothing is sticking to the bottom.
Pour the tomato sauce on top of the water but DO NOT STIR (Stirring the tomato sauce might lead to a burn notice while cooking). However, if you are using tomato paste instead of tomato sauce, then make sure to stir it in to mix it evenly with water.
Place the slit jalapeno on top of everything.
Now close the lid and seal the vent. Cancel the saute mode and turn on the manual mode on high pressure for 6 minutes.
Once the Instant pot beeps and turns off, let the steam release naturally for 10 minutes, and then do a quick to release the rest of the steam by turning the knob to VENT position.
Once all the pressure is released and the pin drops, then open the lid carefully staying away from the steam. Remove the Cooking insert from the Instant pot and leave it on a heat-proof surface for 5 mins without touching the rice.
After 5 minutes when the initial heat has escaped, gently fluff the rice using a fork without smashing it. Now leave it again for a couple of minutes, then garnish with cilantro if you prefer to, and serve it with your favorite Mexican entrees.