Step 1: Reduce the Strawberry Puree.

In a small saucepan, bring the 2 cups of pureed strawberries to a boil over medium heat.

Reduce the heat to a simmer.

Cook, uncovered, for 20-25 minutes, or until reduced to 3/4 cup, stirring occasionally.

Transfer the reduced puree to a shallow container.

Refrigerate until chilled.

Step 2: Preheat Oven and Prepare Pans.

Preheat the oven to 350°F (175°C).

Line the bottoms of two greased 9-inch round baking pans with parchment paper.

Step 3: Cream Butter and Sugar.

In a large bowl, cream the softened butter and sugar together until light and fluffy, 5-7 minutes.

Step 4: Add Egg Whites and Extract.

Gradually beat in the room-temperature egg whites.

If desired, add the strawberry extract.

Step 5: Add Sour Cream.

Mix in the sour cream until combined.

Step 6: Combine Dry Ingredients.

In a separate bowl, whisk together the cake flour, baking powder, baking soda, and salt.

Step 7: Alternate Adding Dry Ingredients and Strawberry Puree.

Gradually add the dry ingredients to the creamed mixture, alternating with 1/2 cup of the reduced strawberry puree.

Begin and end with the dry ingredients.

Mix until just combined. Don’t overmix.

Step 8: Bake the Cake Layers.

Transfer the batter to the prepared pans, dividing it evenly.

Bake until a toothpick inserted in the center comes out clean, 30-33 minutes.

Step 9: Cool the Cake Layers.

Cool the cake layers in the pans for 10 minutes.

Remove from the pans to wire racks.

Remove the parchment paper.

Cool completely.

Step 10: Make the Frosting.

In a large bowl, beat the softened cream cheese and butter until fluffy.

Gradually beat in the confectioners’ sugar.

Beat in 1/4 cup of the reduced strawberry puree and, if desired, the strawberry extract and red food coloring.

Beat until smooth.

Step 11: Assemble the Cake.

Place one cake layer on a serving plate.

Top with the strawberry jam, spreading it evenly.

Top with 1 cup of the frosting, spreading it evenly.

Top with the remaining cake layer.

Spread the remaining frosting over the top and sides of the cake.

Step 12: Garnish and Serve.

Garnish with halved or sliced fresh strawberries, if desired.

Refrigerate until ready to serve.