Cookies in under 20 minutes?

Turn on the oven NOW (180 degrees C) so that it's 'up to temp' by the time you've made up the mixture, which should only take you 5 minutes to do.

Cream together 4oz of butter and 4oz of sugar .. and stir in 8oz of flour, a teaspoon of Vanilla Extract, 4oz of chopped nuts and 4oz chocolate chips.

Roll up into balls, and then press them flat, and then bake for 15 minutes on a sheet of baking parchment.

Biscuits in 20 minutes .. but it is better if you wait for them to cool down !!

Just don't eat them all in under 20 minutes or else you'll get fat

Yes, some cookies only take 10 or 15 minutes to bake once their mixed and shaped. Google some quick cookie recipes.  

Unlikely, if they are being made from scratch. You might do it if you're using an already-prepared dough. Most cookies take ten minutes or longer to bake.

No.  It takes at least that long for the oven to heat up.

The fastest cookies are made from the refrigerated cookie dough that comes in a roll, covered in plastic.  Slice and bake.

Toll House cookie dough can be used to make cookies quickly. 

Try no bake cookies but even that will take longer than 20 minutes to set