Add water to the Instant Pot and set the steamer basket inside.
Place potato in the basket and secure the lid
Cook on “Manual” function for 5 minutes at high pressure.
Release the pressure completely and transfer the drained potatoes into a bowl.
Heat butter in a saucepan over medium heat.
Add garlic and Béchamel sauce, combined cheese and nutmeg powder.
Mix well until smooth then add milk.
Adjust seasoning with salt and pepper. Add steamed potatoes.
Transfer the mixture to a casserole dish and top it with bacon slices, breadcrumbs and cheese.
Bake for about 5 minutes in a preheated oven.
Slice and serve.