With the help of an MAX6816 debouncer from Maxim Integrated to form a single push button power switch. Link here (PDF)
This application note presents a single-pushbutton power-control circuit. The design consists of an ON/OFF control circuit comprised of a push button, debouncer, and flip-flop. This circuit toggles the power output voltage by controlling an LDO.
That seems a little excessive, especially for a design that has non-zero power draw when “off”.
If one has a micro in the design already with 2 spare pins (one to control a FET and one to sense the button), that is a much simpler solution IMHO. Single pushbutton, draws no power when off.