Step 1: Preheat your oven to 180°C (350°F). Grease a 6-cup capacity ovenproof dish (such as a ceramic pie dish or small casserole dish) with butter and lightly sprinkle with granulated sugar, tapping out any excess. Set aside.
Step 2: In a medium mixing bowl, cream together the softened butter and 1/2 cup granulated sugar with an electric mixer until light and fluffy. This should take about 3-5 minutes.
Step 3: Beat in the egg yolks one at a time, ensuring each yolk is fully incorporated before adding the next. Stir in the lemon juice and lemon zest until well combined.
Step 4: Gently fold in the sifted self-raising flour into the butter mixture in two additions, alternating with the milk. Mix until just combined and no dry streaks of flour remain. Be careful not to overmix.
Step 5: In a separate, clean bowl, whip the egg whites with an electric mixer until soft peaks form. Ensure the bowl and beaters are completely grease-free for best results.
Step 6: Gently fold the whipped egg whites into the lemon batter in two stages, using a spatula. Be delicate to retain as much air as possible, which will create a light sponge top for your Self-saucing Lemon Delicious Pudding.
Step 7: Pour the prepared batter into your buttered and sugared ovenproof dish. Smooth the top gently.
Step 8: Carefully and slowly pour the 1 cup of hot water over the back of a spoon directly onto the batter in the dish. This creates the magical self-saucing layer during baking.
Step 9: Carefully place the dish into the preheated oven. Bake for 35-45 minutes, or until the top is golden brown and springs back when lightly touched, and the sauce beneath is bubbling. The cooking time for your Self-saucing Lemon Delicious Pudding may vary slightly depending on your oven.
Step 10: Remove from the oven and let it rest for a few minutes before serving. Serve warm, directly from the dish, with a generous dollop of whipped cream, crème fraîche, or vanilla ice cream. Enjoy your homemade Self-saucing Lemon Delicious Pudding!