In a medium sized saucepan add lemon juice, sugar, egg, and egg yolk. With a whisk, constantly whisk the curd, while heating it up on a medium heat until it starts to thicken.

Then take it off the heat, and pour it through a sieve over a bowl, to catch any cooked egg bits.

Let it sit for 2 minutes to slightly cool down. Then add the cold cubed butter and stir it in while it melts into the curd. Cover the curd with a piece of cling film so it touches the surface of the curd and place it in the fridge. Let it cool down until it’s needed.

Preheat the oven at 170ºC/ 340ºF conventional oven and prepare a 22 cm/ 9-inch round baking pan with parchment paper.

Sift together the all-purpose flour, baking powder, baking soda and salt and set it aside.

In a mixing bowl, add the lemon zest and granulated sugar and with your fingers message them together to release the lemon flavor. Using the paddle attachment or using a hand mixer, add the butter and mix it on medium/high speed for 2 minute.

Add the eggs one at a time into the mixture and mix on low until combined.

Scrape down the sides of the bowl and continue by adding half of the dry ingredients, continuing on low speed, mixing until just combined.

Add the sour cream, lemon juice and vanilla extract and mix until just combined, make sure not to over mix the cake batter.

Add the other half of the dry ingredients, mixing until just combined.

Using a rubber spatula, give the batter a gentle fold to make sure all of the ingredients have combined.

Pour the cake into the prepared pan and bake for 28-32 minutes or until a cake tester comes out clean. It will stay light and won’t brown.

Let the cakes cool on a cooling rack. After 10 minutes, gently remove the cake from the cake tin and let the cakes cool down completely.

Once the cake has cooled down completely, make the frosting. With an electric mixer, cream together mascarpone, agave syrup and vanilla bean paste. Then add the powdered sugar and mix it together until smooth.

Add the heavy cream and whip it until stiff peaks and it holds its shape. Place in the fridge, covered by plastic wrap, until ready to assemble.

Place the cake on your serving plate. Add the mascarpone frosting on top of the lemon cake. Add as much of the lemon curd on top of the mascarpone creme and with a spoon and swirl it together with the frosting.