Preheat your oven to 350°F (175°C). Grease and flour a 9×9-inch baking pan, or line it with parchment paper for easy removal.

In a medium bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.

In a separate large bowl, cream together the softened butter and egg until light and fluffy. Slowly mix in the brewed coffee, buttermilk, and vanilla extract until combined.

Gradually add the dry ingredients to the wet ingredients, stirring until you have a smooth, thick batter with no lumps.

Pour the batter into the prepared pan and smooth the top with a spatula. Bake for 25–30 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.

While the cake cools, make the caramel sauce.

In a small saucepan over medium heat, combine the brown sugar, butter, and heavy cream. Stir constantly until the mixture comes to a simmer. Let it bubble for about 3–4 minutes, stirring often, until thickened.

Remove from heat and stir in the vanilla extract and a pinch of salt. Set aside to cool slightly — it will continue to thicken as it cools.

In a small bowl, whisk together the brewed coffee and powdered sugar until you have a smooth, pourable glaze.

Once the cake is fully cooled, pour the caramel sauce evenly over the top, allowing it to soak in slightly for maximum gooeyness. Then drizzle with the coffee glaze for an extra boost of coffee flavor and a beautiful finish.

Slice and serve with a hot cup of coffee, or even a scoop of vanilla ice cream for the ultimate treat.