Preheat oven to 350°F / 180° C / Gas mark 4.

Butter and flour an 8 x 5 loaf pan. You can also use baking spray with flour.

In a medium bowl, whisk together the cake flour, all purpose flour, baking powder, baking soda and salt. Set aside.

In the bowl of a stand mixer fit with the paddle attachment, or using a handheld electric mixer, beat the butter until light and pale, about 4 - 5 minutes.

Add the sugar and continue to beat on medium speed for an additional 3 - 4 minutes.

Add eggs, one at a time, incorporating the first egg fully before adding the second. Scrape down the sides and bottom of the bowl.

Reduce speed to low and add vanilla, lemon zest and lemon juice.

Add half of the flour mixture, then mix until it is almost fully incorporated, then add buttermilk and continue to mix. Finally, add remaining flour and lemon thyme, then shut off the mixer.

Use a rubber spatula to fold the remaining flour and herbs into the batter, then pour into prepared loaf pan.

Bake for 45 - 55 minutes, until a tester comes out with only a few moist crumbs attached. Remove from the oven and turn cake out onto a cooling rack to cool completely.

Drizzle with lemon glaze once cake is completely cool - Mix confectioner's sugar and lemon juice together in a small bowl with a whisk until smooth.