Preheat the oven to 350.

Prepare a 9 x 13" baking pan by lining with foil or parchment paper and then spray lightly with cooking spray. Set aside.

Sift together the flour, cocoa, baking powder and salt in a medium bowl, then lightly whisk together.

In a small bowl combine the eggs and vanilla, do not mix.

In a stand mixer fitted with a paddle attachment, add the butter and beat on low speed until creamy for 30 seconds.

Turn mixer to medium speed and add the sugar, beat until light and fluffy.

On low speed add the flour mixture in three additions, alternating with the egg mixture in 2 additions, until well blended.

Scrape the sides and bottom of the bowl as necessary.

Pour the batter into the prepared pan.

Bake 30 minutes, until a toothpick inserted into the center comes out clean.

Transfer to wire rack to cool.

Cut brownies into 1-inch cubes and let dry at room temperature for 6 to 8 hours.

Preheat oven to 325.

Butter a 2 quart pate or terrine mold, bread pan, soufflé dish or whatever container that you like.

Prepare a water bath by placing a terry-cloth towel into a roasting pan then place the terrine pan on top. This method prevents your pan from sliding and overcoming.  Set this aside.

In a saucepan over medium heat bring the milk, cream, Baileys and sugar just to a simmer.

Place the chocolate into a medium bowl.

Pour the hot simmering cream mixture over the chocolate then let stand for 3-4 minutes.

Whisk until smooth.

In a small bowl whisk together the eggs and vanilla, then slowly mix this into the chocolate mixture.

To assemble, tightly arrange the brownie cubes and the chopped caramels in the prepared pan, leaving some room at the top for the custard.

Pour the custard over the brownies and let stand.

Using a large spoon press the brownies down into the pan to be sure they are well saturated.

Add more custard then let sit and repeat the process. You want the custard above the brownies.

Pour hot water into the roasting pan; be careful not to get any into the terrine, until the water is half way up the sides of the terrine pan.

Bake until an instant-read thermometer reads 170 F, about 90 minutes.

Be sure to check after 60 minutes of cooking time, then check intermittently.

After terrine is finished, remove from oven to cool.

Refrigerate until well chilled.

To remove terrine from pan, set into a baking pan filled with warm water for a few minutes, then invert onto a cutting board or your serving plate.

Let terrine come to room temperature before cutting.