This one page document has blank lines for students to write a one or two paragraph response to a prompt. (They could attach additional pages as necessary.)
At the bottom of the page, there is a rubric (scaled from 1 to 4) to evaluate capitalization, punctuation, grammar, and spelling.
This was designed for 3rd grade, so you may find that the rubric is too generous for your needs. Since it is in word, you are free to edit the number of mistakes that you allow in each category. This is also a useful thing to do throughout the year, becoming more strict as you teach the mechanics of writing.