Preheat your oven to 350°F (175°C) and lightly grease a 9×13-inch baking dish. In a large mixing bowl, whisk together the self-rising flour, sugar, and salt until evenly combined.

In a separate bowl, mix the melted butter, eggs, buttermilk, and vanilla extract. Pour the wet ingredients into the dry ingredients and stir until a soft dough forms. If using raisins, oats, cinnamon, or nuts, fold them in at this stage.

Spread the dough evenly into the prepared baking dish. Smooth the top with a spatula so the dough bakes evenly throughout. The mixture will be thicker than cake batter but softer than traditional cookie dough.

Bake for approximately 40 to 45 minutes or until the top becomes lightly golden and a toothpick inserted into the center comes out clean. Remove from the oven and allow it to cool slightly.

While the baked loaf is still warm, carefully remove it from the pan and place it on a cutting board. Using a sharp knife, cut it into long rectangular strips or traditional rusk-shaped pieces.

Try to keep the sizes as uniform as possible. Evenly sized pieces will dry at the same rate during the second baking stage, ensuring consistent texture throughout the batch.

Place the cut rusks onto baking trays or wire racks with a little space between each piece. Proper airflow is important because the goal is to remove moisture gradually rather than continue baking aggressively.

Reduce the oven temperature to 200°F (95°C). This low temperature helps dry the rusks slowly while preserving their delicate flavor and preventing excessive browning.

Return the trays to the oven and allow the rusks to dry for approximately 2 to 3 hours. Turn them halfway through the drying process so they become evenly crisp on all sides.

The rusks are ready when they feel dry, firm, and crunchy throughout. Depending on humidity levels and thickness, the drying time may vary slightly.

Remove the rusks from the oven and allow them to cool completely on wire racks. As they cool, they will become even crispier.

Store them in an airtight container at room temperature. Properly dried rusks can remain fresh and crunchy for several weeks, making them perfect for meal prep and everyday snacking.