Preheat oven to 350°F (175°C). Grease and line two 8-inch round cake pans with parchment paper. Set aside.
In a large mixing bowl, beat the softened butter and granulated sugar together for 3–4 minutes until pale and fluffy.
14 tablespoons unsalted butter, 1 cup granulated sugar
Add the eggs one at a time, beating well after each addition. If the mixture looks slightly curdled, add a spoonful of the flour to bring it back together.
4 large eggs
In a separate bowl, whisk together the flour, baking powder, and salt.
1 ½ cups all-purpose flour, 2 teaspoons baking powder, ½ teaspoon salt
Fold the dry ingredients into the butter mixture in two additions. Add the milk with the final addition of flour. Mix just until combined. The batter should be smooth.
2 tablespoons whole milk
Divide the batter evenly between the prepared pans (about 490g per pan for precision) and smooth the tops gently.
Bake for 28–30 minutes. The cakes are ready when: The tops are lightly golden, the centers spring back when gently pressed, a toothpick inserted into the center comes out clean.
Remove from the oven and cool in the pans for 10 minutes, then turn out onto a wire rack to cool completely.
In a mixing bowl, add the heavy cream and powdered sugar then whisk until medium-firm peaks form. The cream should hold its shape while remaining smooth and silky.
¾ cup heavy cream, 2 tablespoons powdered sugar
Place one sponge layer flat-side up on a serving plate. Spread the strawberry jam evenly over the surface.
½ cup good-quality strawberry jam
Top with the whipped cream, spreading gently and leaving a small border around the edge to prevent overflow.
Place the second sponge layer on top, flat-side down. Press gently to settle.
To serve, dust generously with powdered sugar and decorate with fresh strawberries if desired.
Notes
Butter: If using salted butter, omit the salt in the sponge.
Eggs: Traditionally, 240 g of eggs were used in this cake. Since 4 American eggs weighs 200 g, the ingredients were scaled to match the American egg weight.
Flour: In Britain, the cake is often made with self-rising flour. However, after extensive testing, this recipe was developed with flour, baking powder, and salt.
Whipped cream: If you would like tips on how to best make homemade whipped cream, check out my whipped cream recipe post.
Jam: Be sure to use a good-quality jam, not jelly. Strawberry is a popular variation, but raspberry jam is the traditional filling.