Preheat your oven to 275 F.
Prepare your carrots. You can cut them into 1-inch pieces or leave them whole if they will fit all flat in your baking dish.
2 pounds carrots
Mix the zest, lemon juice, garlic, thyme, and fat.
Zest of 2 lemons, Juice of those 2 lemons, 4 cloves garlic, 3 sprigs thyme, 2 cups melted duck fat
Pour the fat mixture into the carrots. It should ideally cover the carrots completely. Add fat if necessary.
Put in the oven for about two and a half hours.
Remove from oven. At this point, the carrots will be soft and delicious.
As an optional step before serving, brown the carrots in a large skillet with the fat mixture that was used for cooking them. This will create a crispy exterior and a tender interior.