Benny,
One thing I have learned about asparagus is the amount of misleading and almost religious guff that is written about them. "I get the asparagus pot boiling and then dash out into the garden to harvest the spears and dash indoors to plunge them into boiling water" from The Telegraph. What tosh. People buy asparagus in supermarkets that's grown in Chile for goodness sake.
The best advice (and this has been verified with many veg growers I've met) is to ...
harvest any spears as tall as the span of your hand or the length of your secateurs
anything taller, just leave to grow on. It'll feed the plant
harvest any spears that are wider than your little finger (or a pencil if you have large hands)
with secateurs and not fancy asparagus cutting knives
up to, but not past, the longest day. The plants need to build up their root-store for next year
feed with your preferred fertilizer in late January or early Feb (I use fish, blood and bone)
That's it.
My wife cooks them in home grown chopped and fried garlic with butter with a bit of olive oil in a griddle pan or frying pan (I am not allowed in the kitchen). Cooked to slightly singed frond-end - delicious.