Step 1

Pour the pasta into the Instant Pot and add the water, soy sauce, mustard, and salt. Stir well to combine, then add the cauliflower on top without stirring, making sure that the cauliflower layer completely covers the pasta for even cooking.

Step 2

Secure the lid and move the steam release valve to Sealing. Select Manual or Pressure Cook to cook on high pressure for 3 minutes. While the pot is coming to pressure, shred the Cheddar (you should have about 1 cup).

Step 3

When the cooking cycle is complete, let the pressure naturally release for 10 minutes (so don't touch the pot until 10 minutes has passed), then move the steam release valve to Venting to release any remaining pressure.

Step 4

When the floating valve drops, remove the lid and stir the pasta well, using a spatula to break up any pasta that has stuck together or stuck to the bottom of the pot. (A little sticking is to be expected, but it will loosen up when you stir.) Use the spatula to mash any intact cauliflower florets against the side of the pot to help them dissolve into the pasta sauce.

Step 5

Add the Cheddar and Parmesan and stir well. Adjust the seasonings as needed and serve warm. Store leftovers in an airtight container in the fridge for 4 days.