And an optional Pinch of salt

Question

I'm big and round but not a plate,

My components could tell you more,

Learn what I am you need not wait,

If you can solve my riddles four.

1)

I open wide for fire's light,

A well placed treasure hides within,

Take this freely I invite,

Plundered by those who can gold spin.

2)

Treasure within I also hide,

A floating viscus golden gel,

Not concerned with what's outside,

Behind a wall of thinnest shell.

3)

Pale colour and container both,

A silky comforting dew,

Perfect fuel for youngling growth,

Each drop a pearl of nature's brew.

4)

Fourth, a product of the third,

More treasure - pale and golden bar,

Absent so much whey and curd,

Now mix well all you've solved so far.

What am I (Yes "hungry" but what else)?

Answer 1

I think you are:

A pancake

Because:

A pancake is big and round but not a plate

My components could tell you more:

The other riddles are the ingredients of a pancake:
1. Flour (Made from a grain, which opens in the light. I think the reference to spinning gold is the story of Rumplestiltskin in which a miller's daughter could spin gold from straw.)
2. Egg (the yolk is golden and viscous, behind a shell)
3. Milk ("fuel" or food for young children)
4. Butter (a product of milk, for frying)

And of course:

An optional pinch of salt.