(egg) yolk
[noun]
[de dooi-er, de dooi-ers]

A "dooier" is the yellow part of an "ei": a yolk. You may also see "eierdooier": egg yolk.

Don’t confuse "dooier" with "dooien": to thaw, to defrost, to stop freezing.

There’s also "dooie", which is spoken language for "dode": dead (person), plural "dooien".

Examples:
– "Hoe wil je de dooier van je gebakken ei? Heel of stuk?" 
("Do you want the yolk of your fried egg? Broken or not?" Lit.: "Intact or broken?")

– "Het scheiden van de dooier van het eiwit is een kwestie van veel oefenen." 
("Separating the yolk from the egg white is a matter of practising a lot.")

Related words:
– Ei: egg [noun] [het ei, de eieren].
– Spiegelei: fried egg, sunny side up (lit.: mirror egg) [noun] [het spiegelei, de spiegeleieren].

Example:
– "Een spiegelei als ontbijt, erg goed om de kater tegen te gaan…"
("A fried egg for breakfast, very good to fight the hangover…" Lit.: "…to go against the hangover…")

– Eierschaal: eggshell [noun] [de eierschaal, de eierschalen].
– Eiwit: 1. egg white [noun] [het eiwit, <no plural>]. 2. protein [noun] [het eiwit, de eiwitten].