Why do cookies get hard after baking?

Related questions

1. Can you refrigerate baked cookies?
2. Are rolled oats and quick oats the same?
3. How do you store cookies so they don't get hard?
4. Do you grease cookie sheet for cookies?
5. Can you reuse parchment paper for cookies?
6. Are Dad's Oatmeal Cookies Healthy?
7. Are oatmeal raisin cookies healthier than chocolate chip?
8. Why did my cookies spread when baked?
9. Is oatmeal with raisins healthy?
10. How far in advance can I make cookies?

Tags

1. #cooking
2. #while
3. #flour
4. #tough
5. #outward
6. #greasy
7. #baking
8. #butter
9. #little
10. #crispy
11. #spread
12. #cause
13. #helps
14. #cookies
15. #crumbly
16. #adding
17. #upward