Recommendation letters

Please help! I am applying to a very selective engineering school and I’m debating between two recommenders (the school only accepts one letter): a science teacher who had me for two years and loves me, but is a bad writer, or an AP english teacher who is an incredible writer, I spent lunch with every day and also loves me...? What’s more important, a letter from the field you’re applying for or a letter that would really make me shine from a field i’m not planning on studying?