Preheat the oven to 350 degrees F.

Grease and flour a large loaf pan.

Zest the lemons. Fillet five of them and juice the 4th one.

Cut the fillets in pieces and in a small bowl toss them with the 1/4 cup sugar. Set aside.

In a separate bowl, whisk together the flour, cornstarch, baking powder, 3 teaspoons of the ground vanilla beans and salt. Set aside.

Beat the 3/4 cup sugar together with the butter until creamy.

Beat in the eggs and sour cream.

Add 1 tablespoon of the lemon juice

Add the zest, reserving 1 teaspoon for the glaze.

Add the dry ingredients and beat until just combined.

Fold in the Meyer lemon pieces.

Transfer the batter to the prepared pan. Place in the oven and bake for 40 minutes or until a knife inserted in the middle of the cake comes out clean.

Remove from oven and let cool for 10-15 minutes. Remove from pan and transfer to a wire rack placed over a parchment lined baking sheet to cool completely.

In a separate bowl, whisk together the remaining lemon juice and the powdered sugar.

Add the 1/2 teaspoon of vanilla beans and remaining teaspoon of zest to the glaze. If the glaze is too thick, add water, one tablespoon at a time until it reaches a pourable consistency.

Pour the glaze over the top of the completely cooled cake.

When the glaze has hardened, slice and serve.