Final answer:
The correct signage should read 'Our pastries are the best in town,' addressing the grammatical errors in the original phrase.
Step-by-step explanation:
When observing the phrase “ARE PASTRYS ARE THE BEST IN TOWN”, it is clear that there are a few grammatical errors to address in order to fix the sign. The corrected sentence should be “Our pastries are the best in town.” The word 'pastrys' should be changed to the plural form 'pastries,' and the first 'are' should become 'our' to make the sentence both grammatically correct and semantically meaningful.