You can earn Gold Vouchers by taking part in Food Club events with your food club.
Food clubs unlock at level 12.
Once you begin to participate in the event by filling orders you will start working towards milestones which are rewarded with coins, gems, tokens and gold, silver and bronze vouchers.
You can see your progress towards your milestones on the progress bar above the event orders.
For more about Food Club Events see our Knowledge base guide to Food Clubs here