Preheat your oven to 350°F (175°C) and line a muffin pan with 12 cupcake liners.

In a mixing bowl, combine granulated sugar and freshly grated lemon zest. Massage until fragrant.

In a separate bowl, whisk together full-fat sour cream, water, vegetable oil, large egg, lemon extract, and vanilla extract until smooth.

In another bowl, whisk together cake flour, the lemon-infused sugar, poppy seeds, baking powder, and fine salt. Gradually add this to the wet ingredients.

Spoon the batter into cupcake liners, filling them about 3/4 full. Bake for 18-21 minutes or until a toothpick comes out clean.

Let the cupcakes cool in the pan for 10 minutes, then transfer to a wire rack.

In a mixing bowl, beat unsalted butter and cream cheese until smooth. Gradually add lemon zest, vanilla extract, fine salt, powdered sugar, and lemon juice.

Optionally, create a hollow in each cupcake and fill with lemon curd.

Frost each cooled cupcake with the cream cheese mixture using a piping bag.