Turn the sauté feature on the Instant Pot and allow it to warm while chopping the garlic.
Once the Instant Pot is hot add the olive oil and garlic and sauté for 30 seconds being careful to not burn the garlic.
Add the orzo and stir to coat with the olive oil while toasting the orzo. After a minute turn off the sauté feature.
Add the water, or broth if using, and the salt, pepper and lemon juice.
Now secure the lid of the Instant Pot. Set the timer for 2 minutes and make sure that you turn the steam valve to the sealing position.
The Instant Pot will take a few minutes to pressurize. You will hear it make slight hissing noises as the steam is building inside the pot. Once it gets to pressure the 2 minute timer will begin to count down.
Once the 2 minutes is up it is time to release the stem or do a quick steam release. Do this by using a wooden spoon to move the steam release valve to the venting position. Be carful to keep your face away as the steam is released.
Now you can remove the lid from the Instant Pot and add the Parmesan cheese and arugula. The heat will melt the cheese and wilt the arugula as you stir it into the orzo.
Let the orzo sit for 2-3 minutes as the pasta absorbs the remaining liquid. The starchy pasta will create a creamy sauce with the cheese.
Serve immediately as a quick vegetarian dish or with protein of choice for a delicious side dish.
Leftover orzo can be stored in an airtight container for 2-3 days and reheated in the microwave with a little splash of water.