1. Prepare Oven and Pans:

• Preheat oven to 325°F (160°C).
• Prepare three 9-inch round cake pans by spraying liberally with non-stick cooking spray. Lining the bottoms with parchment paper is also recommended.

2. Mix Dry Ingredients:

• Sift together the cake flour, baking powder, and salt in a medium mixing bowl. Whisk to combine and set aside.

3. Cream Butter and Sugar:

• In the bowl of a stand mixer fitted with the paddle attachment, beat the room temperature butter and granulated sugar together on medium-high speed until smooth, light, and fluffy (about 3-5 minutes).

4. Add Eggs and Wet Ingredients:

• Reduce mixer speed to medium-low. Slowly add the room temperature eggs and egg white, one at a time, mixing well until combined after each addition. Scrape down the bowl.
• Stir in the room temperature sour cream, vanilla extract, and optional orange extract. Mix well until combined.

5. Alternate Dry Ingredients and Milk:

• Scrape the sides of the bowl. With the mixer on low speed, add about half of the flour mixture. Stir until just incorporated.
• Slowly stream in the room temperature milk while the mixer is running on low.
• Add the remaining flour mixture and stir only until the flour is fully incorporated. Do not overmix. Scrape the sides and bottom of the bowl and give it one final gentle stir with a spatula.

6. Bake the Cakes:

• Divide the batter evenly among the three prepared 9-inch round baking pans. Smooth the tops.
• Bake in the preheated 325°F (160°C) oven for about 35 minutes. Cakes are done when the tops spring back with a light touch, or a toothpick inserted into the center comes out clean.
• Allow cakes to cool in the pans on wire racks for about 10-15 minutes before carefully inverting them onto the racks to cool completely.

7. Prepare Frosting Components:

• Whip Cream: In the clean bowl of your stand mixer fitted with the whisk attachment (or using a hand mixer and a chilled bowl), beat the cold heavy cream on medium-high speed until stiff peaks form. Set aside, preferably in the refrigerator. (Chill the bowl and whisk beforehand for best results).
• Beat Cream Cheese Base: Fit the paddle attachment onto your mixer (clean the bowl if you only have one). Beat the softened cream cheese on high speed until completely smooth and fluffy, scraping the sides a couple of times.
• Add the vanilla extract and granulated sugar to the cream cheese. Beat on medium speed until fully incorporated and smooth.

8. Combine Frosting:

• Remove the mixer bowl from the stand.
• Stir the finely chopped strawberries into the cream cheese mixture using a spatula on low speed just until distributed.
• Gently fold the reserved whipped cream into the strawberry-cream cheese mixture with a spatula until evenly combined and no streaks remain. Be careful not to deflate the whipped cream too much.

9. Assemble the Cake:

• Ensure cake layers are completely cool. If desired, level the tops with a serrated knife.
• Place the first cake layer on your serving platter or cake stand.
• Top with a generous layer of the strawberry frosting (about 1/2-inch thick, maybe slightly more), spreading it evenly to the edge.
• Place the second cake layer on top and repeat with another layer of frosting.
• Place the third cake layer on top (upside down for a flat surface).
• Frost the top and sides of the cake with the remaining strawberry frosting using an offset spatula. Smooth the top and sides as evenly as possible.

10. Garnish and Chill (Optional but Recommended):

• Top with additional sliced strawberries for garnish, if desired.
• Chill the cake for at least 30 minutes to an hour before serving to allow the frosting to set slightly.