I made these last night! Thanks for the great recipe :)
Because I don't own a 20 cm x 20 cm baking dish, I used two long loaf tins (about 30 cm x 10 cm). Otherwise I followed the recipe to a tee. Because of this change, I suspect that I should have reduced the baking time a bit because the brownies came out a bit harder than expected. Next time - because there will be a next time! - I'll buy a new baking dish or I'll reduce the baking time.
Otherwise, they taste lovely. Well done on an awesome site - I really appreciate the thought that goes into your recipes and the scientific approach you have in breaking these things down!