Start by adding the elbow macaroni, butter, nutmeg, salt, chicken stock, and water to the Instant Pot. Make sure the ingredients are well combined. The butter will melt beautifully during cooking, adding richness to the dish.
Close the lid of the Instant Pot and set the valve to the “sealing” position. This step is crucial for building up pressure, which will cook the pasta perfectly.
Press the “manual” or “pressure cook” button, adjusting the timer to 5 minutes. Your Instant Pot will take about 7 minutes to build pressure before it starts cooking.
When the timer goes off, press the “cancel/off” button. Allow the pot to sit for one minute to let the pressure release slightly, then switch the valve to quickly release the remaining pressure. Be sure to stand back and open the lid carefully, away from your face, to avoid steam burns.
Stir the macaroni with a wooden spoon, noticing how perfectly it’s cooked. The pasta should be tender yet firm, providing a delightful texture.
Add the evaporated milk to the pot. Stir well to combine with the pasta, creating a creamy base for your cheese.
Gradually add the cheddar cheese, half a cup at a time, stirring until melted and smooth. This method ensures that the cheese incorporates evenly and prevents clumping.
Add the mozzarella cheese, continuing to stir until you reach the desired consistency. You can adjust the amount of cheese based on how cheesy you want your dish to be.
Finally, season with black pepper, giving it a final stir. The black pepper adds a hint of spice that complements the rich flavors of the cheese.
Your Instant Pot Mac and Cheese is ready to be served! You can enjoy it immediately or transfer it to a baking dish for a crispy breadcrumb topping if desired.