Preheat the oven to 350 degrees F (175 degrees C). Line a loaf pan with parchment paper.

Combine flour, sugar, butter, eggs, and lemon curd in a bowl or food processor. Mix well. Place into the prepared pan.

Bake in the center of the preheated oven until a toothpick inserted into the middle of the cake comes out clean, 60 to 90 minutes.

Blend lemon juice, white sugar, and lemon zest together in a bowl while cake is baking.

Let cake cool in the pan, 2 to 3 minutes. Pour the lemon-sugar topping over the warm cake to let soak. Allow to cool, about 30 minutes. Turn cake out of the pan.