Preheat oven to 180 degrees C. grease and flour the bundt pan.

In a medium bowl, sift together the flours, baking powder, baking soda and salt.

Grate the zest from the two lemons, and juice one of them.

In a large bowl, beat together the butter and sugar using an electric cake mixer on medium speed till they come together, then beat on high speed till they turn very light and fluffy.

Add in the eggs, one at a time, beating well after each addition. scrape the bowl often using a spatula.

Add in the lemon zest and vanilla.

Turn the speed to low, and add one third of the flour mixture. beat till incorporated.

Next add the lemon juice, followed by another third of the flour mixture, then the sour cream, and the last of the flour mixture. beat well after each addition.

When the batter is smooth and even, stir in the pecans (do not beat!)

Pour the batter into the prepared bundt pan, and bake for 50 to 60 minutes.

When a knife inserted in the center of the cake comes out clean, remove it from the oven.

Let it cool in the pan for 10 minutes, and while still warm, invert it onto a wire rack.

Cool on the wire rack till room temperature.

Optional: you can top the cake with a lemon glaze and/or toasted chopped pecans.