I used 1.5 tsp per cup of heavy whipping cream and let it steep in the fridge all day.
It's a good idea to chill your bowl and your wisk prior to whipping the cream. Strain tea from the cream & add your sugar at this point. If using matcha instead of tea leaves, add it now.
Mix on medium-medium/high speed if using a mixer, or you can whisk by hand. Be careful not to over do it.