Step 1

Add the bacon to the Instant Pot® and turn the pot on the high saute setting (See Cook's Note). Cook the bacon, stirring occasionally, until golden brown and crisp, 10 to 12 minutes. Remove from the pot and set aside on a paper towel.

Step 2

Add the mushrooms to the pot along with the thyme leaves and a pinch of salt. Cook, stirring occasionally, until the mushrooms have reduced to half their size and are golden brown, 6 to 8 minutes. Remove the mushrooms from the pot and divide the mushrooms among the cups of a silicone egg bites mold. Divide the spinach among the cups, along with the bacon and cheese.

Step 3

Gently whisk the eggs together with the cream, nutmeg and 1/2 teaspoon salt and a few grinds of pepper in a medium bowl until well combined (gently to avoid creating foam). Pour the custard over the fillings in each of the cups.

Step 4

Wipe out excess bacon grease in the bottom of the pot. Add 1 cup water to the bottom of the pot. Place the egg cups on the rack and cover tightly with the silicone lid or foil. Lower into the pot using the rack handles and follow the manufacturer's guide for locking the lid and preparing to cook. Set to pressure cook on low for 6 minutes.

Step 5

After the pressure cycle is complete, let the pressure release naturally for 10 minutes, then follow the manufacturer's guide for quick release of the remaining pressure. Be careful of any remaining steam and unlock and remove the lid. Carefully remove the tray and let stand 5 minutes before popping the mini frittatas out of the pan. The frittatas can be eaten right away or stored in the trays in the refrigerator or freezer; reheat in the microwave for 30 seconds to 1 minute.