In this sentence shouldn't the verb be in the singular form?
'Of a particular note are the Thai restaurants,which are amongst the best I've ever encountered so far.'
"Are" is correct but the "a" shouldn't be there. The phrase is "Of particular note", which can then be followed by "is" or "are" (or variations thereof) depending on the form of the noun which follows. "Are" is correct here because it's followed by "the Thai restaurants" which is plural.
Of particular note are the Thai restaurants...