Currently, two restaurants are serving lab-grown meat: https://santemagazine.com/the-first-two-restaurants-serving-cultivated-meat-in-the-u-s/.
Other than that, it is not commercially available. This market will resolve to yes in the event that one can readily buy lab grown meat from a restaurant, store, or directly from the manufacturer in an "easy" way such as clicking a buy button on a site. Methods that require entering into a contract like those that the restaurant and UPSIDE are in will not count.
If this does not happen by 12:00 AM Jan 1 2025 Central Time, this market will resolve to NO.

EDIT: I have realized that the resolution criteria appears a bit vague. To be clear, if the meat becomes available in any other restaurant, or can be purchased from any store or directly from the manufacturer, this market will resolve to yes. If one of the two restaurants opens another restaurant under the same name but in a different location, that will be sufficient to resolve to yes.