Step 1

Mix macaroni, chicken stock, water, sea salt, mustard, and butter in the instant pot.

Step 2

Set Instant Pot to manual, 4 minutes.

Step 3

Quick release after timer goes off.

Step 4

Set to sauté/low.

Step 5

Stir in milk.

Step 6

Stir in cheese 1/4 at a time.

Step 7

Turn off heat and serve!

Step 8

Optional breadcrumb topping: Transfer after adding all the cheese to a 1.5 to 2-quart broiler-safe dish. Top with 1/4 cup breadcrumbs and broil on high for 5 minutes, or until crumbs start to brown.