1. **Preheat:** Preheat your oven to 350°F (175°C). Grease and flour a 9-inch square baking pan or a round cake pan.

2. **Mix Dry Ingredients:** In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

3. **Cream Butter & Sugar:** In a large bowl or stand mixer, beat the softened butter and granulated sugar together on medium-high speed until light and fluffy (about 3–4 minutes).

4. **Add Wet Ingredients:** Beat in the egg and vanilla extract until fully incorporated. Scrape down the sides of the bowl.

5. **Combine:** Reduce mixer speed to low. Add the flour mixture in three parts, alternating with the buttermilk and the ½ cup cooled coffee. Mix just until combined and smooth. Do not overmix.

6. **Bake:** Pour the batter into the prepared pan and smooth the top. Bake for 30–35 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs.

7. **Poke:** Remove the cake from the oven. Let it cool for just 5 minutes. While still warm, use the handle of a wooden spoon or a chopstick to poke holes all over the surface of the cake (about 1 inch apart).

8. **Make Glaze:** In a small bowl or measuring cup, whisk together the caramel sauce, heavy cream, and 1 tablespoon coffee until smooth and pourable. (Warm it slightly in the microwave if it’s too thick).

9. **Soak:** Slowly pour the coffee-caramel glaze over the warm cake, aiming for the holes so it soaks into the crumb. Spread any excess over the top with a spatula.

10. **Cool & Serve:** Let the cake cool completely in the pan to allow the gooey layer to set slightly. Serve warm or at room temperature, topped with whipped cream or crunchy toffee bits.