I have a thermostat/furnace combination that results in a hyper system --
sometimes the furnace turns on for a minute or less, turns off for a minute
or less, etc. This gets annoying.

I would like to reduce the frequency of switching on and off. In other
words, if it turns on, stay on longer. When it turns off, stay off longer.
This may results in more temperature fluctuation, which is ok.

So, is there a thermostat that allows me to control either: minimum on/off
duration or the on-temperature and off-temperature independently?

My temporary hack is to cover the thermostat with a box. This delays the
temperature change at the thermostat and lengthens the on/off cycle
duration. But I'd rather not have a box on the thermostat.

The current thermostat is a honeywell low voltage system, bought some 10
years ago.