I am baking a cake and I want to substitute some of the flour for ground almonds. Do I substitute 1 for 1 or do I need to use a different ra

Thank you! These answers are very helpful!!

A Victoria Sponge is very light and airy I think, IMHO you would not do 1 to 1, I would add an ounce or 1.5 oz of ground almonds. I looked at an almond genoise recipe and they called for 1/3 cup almond flour and 1/2 cup AP flour. Having never made a Victoria Sponge but I have eaten it before at least the one I had was quite light and the almonds would make it heavier so I would go a little lighter on the almonds.

It's hard to say without trying it, but there are plenty of nut cake recipes that don't call for flour. When you substitute almond flour for regular flour you usually need more leavening, so these cakes often have more baking powder and/or whipped egg whites. Here's an example: http://www.epicurious.com/recipes/food/views/Flourless-Lemon-Almond-Cake-385

Can you refer us to the cake recipe? May help to see the other ingredients and proportions? If you add a link here, we can take a look.