When measuring the flour spoon the flour into the measuring cup rather than using the cup to scoop out the flour. The first cup can be full, but make the second one just a little bit short.
Toast the walnuts by placing them on a baking pan in the oven for 5-10 minutes or until fragrant. You can go ahead and put them in right when you start the oven, no need to wait until it is fully pre-heated!