I made the WASC cake but switched up the ingredients a little too much I think. I made 1 orange and 1 lemon cake. I used flavoured yogurt instead of the sour cream and for the liquids I used frozen fruit juice concentrates. (No water) The lemon cake was dense, very crumbly but not really dry, the orange cake was dense, moist but heavy. But after all that they tasted great, the lemon cake was wonderful.
How do I achieve the great intense lemon or orange flavour but avoid the heavy dense crumbly cake? TIA

I use extracts for flavoring.... Can always use a bit more to increase the flavor intensity.

Improper mixing is probably one of the main reasons for cake failures...

So, when it comes to mixing, MORE (as in more speed or longer mixing time) is not BETTER. Overmixing will develop the gluten and result in a tough cake. Overmixing will also cause a cake to sink.

If using a stand mixer, beat for the recommended amount of time using the LOWEST speed (but don't let the motor strain).

If using a hand mixer, beat for the recommended amount of using using the MEDIUM speed (but don't let the motor strain).

(I would say that improper measuring is also a big deal.) How are you mixing/baking the recipe.

One of the basic techniques in scratch baking is measuring flour accurately.
When measuring flour, do you use the "scoop and drag" method and then shake to level.... You should be aerating the flour prior to gently spooning it into the measuring cup and using a straight edge to level.

Additionally, sifting your cake mix will elimimate those pesky "lumps" that just can't be beaten into submission by faster/longer mixing (which also over develops the gluten).

When I make any of the WASC cake recipes, I sift all the dry ingredients together into a large bowl, and mix all the wet ingredients in a second larger bowl.

Then I add the dry to the wet and beat for 2 mins. using an electric hand mixer at medium speed.

If using a stand mixer, I would mix at the lowest speed for 2 mins. or less.

Handy cake trouble shooting charts:

http://tinyurl.com/2p5bdu

http://tinyurl.com/32goqe

http://tinyurl.com/6c745g

http://tinyurl.com/6lpjww

http://tinyurl.com/yay22w

HTH