In a large mixing bowl, combine the diced chicken, carrots, celery, peas, chopped onion, and minced garlic. This mixture will be the base of your pot pie filling.

Add the chicken broth, heavy cream, dried thyme, dried rosemary, salt, and black pepper to the bowl. Stir well to combine all ingredients evenly.

Transfer the filling mixture into the crockpot, spreading it out evenly. This ensures that all ingredients cook uniformly.

Cover the crockpot with its lid and cook on low for 6 hours or high for 3 hours. This slow cooking allows the flavors to meld and the chicken to become tender.

In a separate mixing bowl, whisk together the flour, baking powder, and salt. This helps to aerate the flour for a lighter biscuit.

Cut in the cold cubed butter using a pastry cutter or your fingers until the mixture resembles coarse crumbs. This step creates flaky layers in the biscuits.

Pour in the milk and stir until just combined. Do not overmix; a few lumps are okay.

After the filling has cooked for 6 hours on low or 3 hours on high, drop spoonfuls of the biscuit dough over the top of the filling. This will create a rustic topping.

Cover the crockpot again and cook on high for an additional 30 minutes, or until the biscuits are cooked through and golden on top.

Once the biscuits are golden and cooked through, carefully serve the chicken pot pie hot from the crockpot. Enjoy the comforting flavors!