Step 1

Pour milk into a 6-qt. Instant Pot electric pressure cooker with a Yogurt setting. Lock lid in place; set pressure valve to "Sealing." Press "Yogurt" button to select the yogurt program. Press "Adjust" button to "More" mode; the word "boil" will appear on the display. The cooker will take about 25 minutes to heat the milk to 180°F. When cycle is complete, cooker will beep and display "yogt." Open lid. Use a quick-read thermometer to make sure the milk registers 180°F.

Step 2

Transfer cooker insert to a large bowl of ice water. Stir milk 2 to 3 minutes or until it cools to 115°F. In a small bowl whisk together 1 cup of the cooled milk and the Greek yogurt until smooth. While whisking constantly, slowly pour milk-yogurt mixture into remaining cooled milk in cooker insert.

Step 3

Return insert to cooker base. Lock lid in place; set pressure valve to "Sealing." Press "Yogurt" button, press "Adjust" button to "Normal" mode, and use the "+" button to set for 8 hours. When cycle is complete, cooker will beep and display "yogt." Open lid.

Step 4

Divide yogurt among four storage containers and chill 3 hours. Store in refrigerator up to 2 weeks.