Firstly, you don’t need to complete the delivery before recording the payment in Breww (there doesn’t need to be an invoice before a payment can be logged). I’d suggest using the Log payment button on the mobile app to record the cash payment before completing the delivery.
We also would recommend not manually recording the payment in both Breww and your accounting software. Just record it in Breww and let Breww put it in your accounting software for you.
In addition, we already have a feature that could act as a handy safety check for if you complete the delivery first accidentally. Please update the selected option for When should Breww automatically send an email with the PDF invoice attached (with the exception of SIBA orders)? in your Order/invoice settings (see here).
There is an option named Automatically send when delivery is completed (sent 10 minutes after to give time for signatures to be added). The 10-minute delay on emailing gives time for payments (and signatures) to be added before the email goes out.
Please let me know either way if these solutions work for you. Cheers.