"Your pasta is dry!"
Translation:הפסטה שלכם יבשה!
The final word describes the pasta (assuming it's an adjective), which is singular. Therefore it wouldn't be 'מלאים' or anything plural. Secondly, it says here dry, which is יבש and not מלא or מלאים. It also should be noted that פסטה is feminine in Hebrew, therefore we'd user יבשה and not יבש. It's correct that whenever you say 'your' it could have plenty of meanings in Hebrew, including שלך and שלכן, also שלכם. So, you could say - הפסטה שלך יבשה, הפסטה שלכם יבשה, הפסטה שלכן יבשה