cut off and discard stalks and fronds; slice 1cm off the base; remove and discard 2 outer leaves; trim the base a bit more; wash and pat dry; slice into quarters then across, very thinly.
place butter in small pot, melt it, then add sliced fennel and let it sweat, lid on, for 5 mins.
add cream and salt, stir, put the lid back on, and simmer 15 mins until soft, stirring occasionally.
take off the heat, uncover and let the moisture evaporate as it cools.
blitz to a smooth purée using a food processor or stick blender.
re-heat and serve, or store refrigerated in a sealed container until ready to use.
Notes
1 serving = 80g.
To turn it into a soup, simply add stock broth (chicken works best) until you get your desired consistency, and adjust seasoning.
The only way to ensure accurate measurement of ingredients is with Metric Kitchen Scales.