Add DRY PASTA, WATER, and SALT to the Instant Pot. Push pasta under the water to submerge it.
Place KIELBASA sausages on top of the pasta. Scatter BUTTER in the pot.
Secure the lid; turn pressure valve to "Sealing" and pressure cook on HIGH for 2 minutes followed by a full 10-minute natural pressure release (NPR). *See recipe notes
Safely turn pressure valve to "venting" position and release any remaining steam. Open the lid, transfer KIELBASA to a plate, slice into ¼" pieces, and add back to the pasta.
For the mac and cheese sauce
Add MILK, DIJON, and CHEDDAR CHEESE to the pasta, gently stirring until the cheese melts and sauce becomes creamy. * See recipe footnote about adding more cheese
Mac and cheese storage and reheat instructions
Store mac and cheese in an airtight container up to five days in the refrigerator.To reheat, add a splash of liquid to moisten the macaroni and reheat via stove or microwave, stirring as needed.
Pressure cook time and NPR
Thicker pasta (macaroni, penne, rotini, etc) gets 2 minutes + 10 minute NPR.
Thinner pasta (shell, spaghetti noodles) gets 1 minute + 10 minute NPR.
Do not cut the 10 minute NPR (natural pressure release) short because it helps prevent splattering and, more importantly, the pasta is still cooking.Want your mac and cheese cheesier?Stir in additional cheese in 1 cup amounts, adding a splash of milk or water as needed to help smooth it out.Kielbasa TipsCaramelization hack - For enhanced flavor, slice the Kielbasa and saute it in the Instant Pot before pressure cooking it with the pasta. This will brown the surface and make it even more heavenly.Substitutions - You can sub any smoked sausage, bratwurst, chorizo, or hot dogs using the same recipe instructions.