Prepare lemon curd ahead, as directed. Keep chilled until ready to use.

Preheat oven to 350°F. Line a cupcake pan with 8 paper liners.

In a large bowl or stand mixer, cream together butter and sugar, mixing until light and fluffy. Mix in egg, lemon zest, lemon juice and vanilla extract until smooth. Scrape the bowl as needed. Add salt and baking powder, mixing until just combined. Alternate additions of flour and sour cream until fully combined and no streaks remain.

Divide batter between prepared baking cups, using a large cookie scoop or filling roughly 2/3 full. Bake for 18-20 minutes or until a toothpick inserted comes out clean. Cool in pan until easy to handle, then transfer to a wire rack to cool completely.

When cupcakes have cooled, prepare frosting. In a large bowl or stand mixer, beat together butter, vanilla, strawberry jam and strawberry extract until fully combined. Add powdered sugar in batches, mixing until fully combined. If desired, add 1 drop red gel food color for a brighter shade of pink.

Transfer frosting to a large piping bag fit with desired piping tip. Set aside. 

Using a sharp knife or cupcake corer, remove the center of each cupcake. Be careful not to cut all the way to the bottom. Fill with lemon curd using a spoon or pastry bag. Trim off the bottom portion of the removed cupcake core, placing the top back onto the cupcake. Frost cupcakes with prepared frosting as desired. Top off each cupcake with a fresh strawberry prior to serving. 

Store cupcakes in an airtight container at room temperature or in the refrigerator for up to several days.