Step 1: Preheat the Oven - Preheat your oven to 350°F (175°C). This ensures that the cake bakes evenly.
Step 2: Prepare the Cake Pan - Grease a 9-inch round cake pan and set it aside. You can use butter or a non-stick spray for this.
Step 3: Combine Dry Ingredients - In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, salt, and ground nutmeg until well combined.
Step 4: Mix Wet Ingredients - In a separate bowl, whisk together the buttermilk, grated lemon zest, freshly squeezed lemon juice, melted butter, and egg yolks until smooth.
Step 5: Combine Wet and Dry Mixtures - Gradually add the wet ingredients into the dry ingredients, stirring gently until just combined. Be careful not to overmix; a few lumps are perfectly fine.
Step 6: Whip Egg Whites - In a clean bowl, beat the egg whites until foamy. Gradually add the remaining granulated sugar, continuing to beat until stiff peaks form.
Step 7: Fold in the Egg Whites - Gently fold the whipped egg whites into the batter using a rubber spatula. This will help create a light and airy texture in the cake.
Step 8: Add Blackberries - Fold in the fresh blackberries gently, being careful not to break them up too much.
Step 9: Pour Batter Into Pan - Pour the batter into the prepared cake pan, spreading it evenly.
Step 10: Bake - Bake in the preheated oven for 35-40 minutes, or until the top is golden brown and a toothpick inserted in the center comes out clean.
Step 11: Cool - Once baked, remove the cake from the oven and allow it to cool in the pan for 10 minutes. Then, invert it onto a cooling rack to cool completely.
Step 12: Serve - Once cooled, dust the top with powdered sugar and serve your Blackberry Lemon Pudding Cake warm or at room temperature. Enjoy the delightful combination of flavors!