Pour the ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized (and ½ cup heavy cream optional but adds extra richness and creaminess if using) into the Instant Pot inner pot. Secure the lid and press the 'Yogurt' button, then press 'Adjust' until the display reads 'Boil'. The Instant Pot will heat the ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized to about 180–185°F (82–185°F) — this takes roughly 30–40 minutes. When it beeps, remove the lid and use a Meat Thermometer to confirm the temperature.

Remove the inner pot from the Instant Pot and set it on a Wire Rack or trivet on the counter. Let the ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized cool, uncovered, until it reaches 105–115°F (40–115°F). This takes about 30–60 minutes. You can speed this up by placing the pot in an ice bath. Stir occasionally and use a Meat Thermometer to check — if the ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized is too hot it will kill the cultures.

Scoop out about ½ cup of the warm ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized into a small Mixing Bowl. Add the ½ cup plain yogurt store-bought with live active cultures, used as starter starter and whisk until completely smooth with no lumps. Pour this mixture back into the inner pot and whisk gently to combine evenly throughout the ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized.

Return the inner pot to the Instant Pot. Place the lid on (or use a glass lid — the pressure valve does not need to be set). Press the 'Yogurt' button and set the time for 8 hours using the '+' button. The display will count up. Do not open the lid during incubation. The longer you incubate, the tangier the yogurt — 8 hours gives a mild tang, up to 10 hours for a sharper flavor.

When the cycle is complete, the ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized will look set but still a bit loose — that's normal. For regular ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized, transfer directly to jars or a large Mixing Bowl and refrigerate for at least 4 hours until cold and thickened. For Greek-style ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized, line a Sieve with cheesecloth, set it over a large Mixing Bowl, pour in the ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized, and refrigerate for 2–4 hours to drain off the whey until you reach your desired thickness.

Stir the finished ½ cup whole milk cold, straight from the Refrigerator — do not use ultra-pasteurized until smooth. Taste and add vanilla extract stir in 1 tsp after incubation for vanilla yogurt or a drizzle of honey drizzle or maple syrup as a natural sweetener alternative to honey if desired. Serve topped with fresh fresh berries strawberries, blueberries, or raspberries and granola for crunch, or use as a base for smoothies, dips, and dressings. Reserve ½ cup of your homemade ½ cup whole milk cold, straight from the fridge — do not use ultra-pasteurized as the starter for your next batch.