Preheat over to 160C. Beat butter in the bowl of an electric mixer until light and fluffy. Add the vanilla and Natvia and beat until combined.
Add the eggs one at a time, beating until each is fully incorporated to the batter.
Sift a small amount of the flour into the batter, beat until combined.
Add 1/3 of the milk and beat until incorporated. Sift over more of the flour and beat until combined. Continue alternating between the flour and last two thirds of remaining milk.
Add the lemon zest and beat until just combined. Pour into a 25cm cake loaf tin.
BAKE for 35-40 minutes or until a skewer inserted comes out clean.
Let stand in the tin for 10 minutes. Poke holes in the cake with a skewer.
Make the glaze by heating the lemon juice and Natvia in a saucepan over medium heat, stirring until the Natvia has dissolved and the mixture starts to bubble. Let the mixture bubble for 30 seconds and then remove from heat. Sift over 1 tbs cornflour and whisk until smooth.
Pour the glaze evenly over the cake before removing to a wire rack to cool.