### Instructions:
1. **Preheat & Prep:** Preheat your oven to 350°F (175°C). Lightly grease a 9×13 inch baking dish.
2. **Combine Dry Cake Ingredients:** In a large bowl, whisk together the flour, ¾ cup granulated sugar, ¼ cup cocoa powder, baking powder, and salt.
3. **Combine Wet Cake Ingredients:** In a separate medium bowl, whisk together the milk, vegetable oil, and vanilla extract.
4. **Combine & Pour Cake Batter:** Pour the wet ingredients into the dry ingredients and mix until just combined. Do not overmix. Pour the batter evenly into the prepared baking dish.
5. **Prepare Pudding Topping:** In a small bowl, whisk together the ½ cup granulated sugar and ¼ cup cocoa powder for the topping. Sprinkle this mixture evenly over the cake batter in the pan.
6. **Add Hot Water:** Carefully pour the 1 ½ cups hot water (or hot coffee) over the sugar and cocoa powder layer. Do not stir! It will look liquidy, but trust the process.
7. **Bake:** Bake for 30-35 minutes, or until the cake is set and a wooden skewer inserted into the cake (not the sauce) comes out clean. The sauce at the bottom will still be bubbling and gooey.
8. **Serve:** Let the cake cool slightly before serving warm. This allows the sauce to thicken beautifully. Serve plain, or with a scoop of vanilla ice cream or a dollop of whipped cream!
### Short Tips:
* **Hot Coffee for Extra Flavor:** Swapping hot coffee for hot water in the pudding sauce deepens the chocolate flavor significantly. Highly recommended!
* **Don’t Stir the Sauce:** It’s crucial not to stir the hot water and cocoa/sugar mixture on top. The magic happens as it bakes and sinks, forming the luscious sauce.
* **Serve Warm:** This cake is best served warm, allowing the hot fudge sauce to remain perfectly gooey.
* **Storage:** Store any leftovers covered at room temperature for up to 2 days, or in the refrigerator for up to 4 days. Reheat gently in the microwave if desired.
* **Garnish Ideas:** A sprinkle of chocolate shavings, a few fresh raspberries, or a dusting of powdered sugar can elevate the presentation.
