Add the sour cream, cream cheese, mayonnaise and French onion soup mix into the Thermomix bowl.
Mix for 15 seconds/speed 3. Scrape down the sides with a spatula and fold the mixture together, making sure the onion powder is mixed through. Mix for a further 10 seconds/speed 3, until combined.
Transfer to a bowl and refrigerate for at least 30 minutes before serving. This allows the onion flavour to develop and the soup mix to soften.
Serve with crackers, corn chips or vegetable sticks.
Notes
Storage: Store the dip in an airtight container in the fridge for up to 3 days.