Tear off 3 large pieces of foil and lay side to side on a flat surface. Slightly curve up the edges so the lemon juice doesn't "roll off" the sides.
Divide the asparagus equally between the three foil packets.
Slater each piece of salmon with 1/2 tablespoon of garlic and place directly on top of the asparagus.
Add 1 tablespoon of lemon juice over the salmon (repeat for each salmon piece).
Sprinkle salt to taste on top of the salmon.
OPTIONAL- sprinkle each piece with red pepper flakes and/or drizzle with honey.
Place one tablespoon of butter on top of the salmon (repeat for each salmon piece).
Tightly close up each piece of foil to ensure no steam can escape.
Add 1.5 cups of water to the bottom of the Instant Pot and insert the metal trivet that came with the machine.
Place the 3 foil packets on top of the trivet (they can be stacked).
Close the Instant Pot and make sure the valve is set to sealed.
Click the "steam" button and set for 4 minutes.
Once the time goes off, hit cancel and QR.
Using tongs, remove the foil packets and carefully open to release the steam and stop cooking.
Transfer the entire contents of the packets (including the butter sauce) to a plate.