Make the Biscuit Base:

1. Preheat the Oven:
   Preheat your oven to 375°F (190°C) and line a 9×9-inch baking dish with parchment paper or grease it lightly with butter.
2. Mix Dry Ingredients:
   In a large bowl, whisk together the flour, sugar, baking powder, and salt.
3. Cut in the Butter:
   Add the cold, cubed butter to the flour mixture. Use a pastry cutter, two forks, or your hands to cut the butter into the flour until the mixture resembles coarse crumbs.
4. Add Milk and Vanilla:
   Pour in the milk and vanilla extract, and stir until the dough just comes together. Be careful not to overwork the dough.
5. Shape the Dough:
   Turn the dough out onto a lightly floured surface and gently roll or pat it into an even 1-inch thick rectangle. Cut the dough into squares or circles (depending on your preference) and place the biscuits into the prepared baking dish.
6. Bake the Biscuit Base:
   Bake the biscuits in the preheated oven for about 15-18 minutes, or until golden brown. Once done, remove from the oven and set aside.

Make the Caramel Sauce:

7. Melt the Butter:
   In a saucepan over medium heat, melt the butter.
8. Add the Sugar and Cream:
   Stir in the brown sugar and heavy cream. Bring the mixture to a gentle simmer, stirring constantly. Once the sugar is dissolved and the caramel sauce thickens slightly (about 5-7 minutes), remove the saucepan from the heat.
9. Finish the Caramel Sauce:
   Stir in the vanilla extract and a pinch of salt. The sauce will thicken further as it cools, but it should still be pourable.

Assemble the Caramel Biscuit:

10. Layer the Biscuits:
    Once the biscuits have cooled slightly, drizzle a generous amount of the caramel sauce over the top, making sure each biscuit gets a good coating.
11. Add Optional Toppings:
    If desired, melt the chocolate chips in a microwave or over a double boiler and drizzle the melted chocolate over the caramel-coated biscuits. You can also sprinkle a pinch of sea salt on top for added flavor contrast.
12. Chill (Optional):
    If you’d like a firmer caramel texture, refrigerate the caramel biscuit for about 30 minutes before serving, allowing the caramel to set slightly.

Serve:

13. Serve and Enjoy:
    Serve the caramel biscuits warm or at room temperature. They’re perfect as a sweet treat with a cup of coffee or as a dessert after dinner.