Since there tends to be some confusion concerning the two, and which one is the correct spelling, I am going to help you understand the difference between the two.
Actually, there's a big difference!
Dolce is Italian for sweet. It is a common musical term, and often used when one is to play the music in a sweet manner.
This is what the dictionary has to say about it.
dolce |ˈdōl ch ā|
adverb & adjective Music
(esp. as a direction) sweetly and softly.
ORIGIN Italian, literally ‘sweet.’
Dulce is another thing entirely. Dulce does mean sweet, but it's meaning is slightly different since it is directed at food.
The dictionary says this about it.
a sweet food or drink, esp. a candy or jam. [ORIGIN: Spanish.]
sweet or mild. [ORIGIN: from Latin dulcis.]
Now you know the difference between the two...and why my blog says Dolce instead of Dulce! I am quite certain after all, that my music is not food!