What does this quote from Klng Iear mean?

I just need the just of it, but detail would also be nice.....

FOOL
No, faith, lords and great men will not let me. If I had a
monopoly out, they would have part on 't. And ladies too—
they will not let me have all fool to myself; they'll be
snatching. Give me an egg, nuncle, and I'll give thee two
crowns.

KING LEAR
What two crowns shall they be?

FOOL
Why—after I have cut the egg i' th' middle and eat up the
meat—the two crowns of the egg. When thou clovest thy
crown i' th' middle, and gavest away both parts, thou borest
thy *** o' th' back o'er the dirt. Thou hadst little wit in thy
bald crown when thou gavest thy golden one away. If I
speak like myself in this, let him be whipped that first finds
it so.

***Translated by No Fear Shakespeare***

FOOL
No. I wish I could be a complete joker—but so many lords and important men are also playing fools that I can't have a monopoly on it. Ladies too—they're always snatching away my role as the biggest fool.—Uncle, give me an egg, and I'll give you two crowns.

KING LEAR
Which two crowns would those be?

FOOL
Well, when I cut the egg in half and eat the whites, the yolk will be in two parts like two golden crowns. When you cut your own crown and kingdom in half and gave away both parts, you were as foolish as the old man in the old story who carries his donkey on his back instead of letting the donkey carry him. You didn't have much brains inside the bald crown of your head when you gave away the gold crown of your kingdom. If I'm telling the truth like a fool in saying all this, whip the first person who thinks I sound foolish.

The gist (or essence) of this passage concerns the failure of seemingly rational people to recognize the difference between wisdom and foolishness.

Lear acted foolishly when he banished his honest daughter Cordelia and relinquised his kingdom and authority to his duplicitous daughters Regan and Goneril. He compounds this error by failing to recognize his foolishness and by failing to comprehend the Fool's counsel. Lear mistakenly believes that if he wears the trappings of a king he must be wise, and that the Fool, dressed in motely (the traditional costume of a fool) must be simple minded.

In order to illustrate Lear's error, the Fool makes imaginative use of a broken egg. When the egg was whole, it represented the strong, unfractured nation that Lear once ruled, what the Fool calls Lear's "golden crown." When broken, the egg's "meat" (the yolk and egg white, in other words, its inherent value) is quickly lost, and all that is left are two empty shells. These shells may look like crowns, but only a fool would mistake their worthlessness for something valuable.

One aspect of Shakespeare's genius is that his images can be plumbed forever and make sense at all levels. Take this image of the egg.

The eggshell is smooth and hairless...like a bald pate. Lear yields his golden crown...the egg's yolk is yellow, like gold, but is spilled out when the egg is cleaved.

I can't believe that Shakespeare consciously worked out all the ways that his images and metaphors would lead. He probably just wrote down whatever came into his mind. But what a fantastic mind that was!

Nick mentions the eggshell as being like a bald pate, so one can also look at the shell as a head and the inside as being the mind; which the breaking of and spreading out metaphorically illustrates the King 'losing his mind' and acting like a fool.