Preheat water bath to 167°F (75°C).
Season the rabbit with salt, pepper, and garlic powder. Sear in a pan over high heat (use a torch concurrently to get all of the areas that don't have contact with the pan) until nicely browned.
Remove from the pan, and immediately add the garlic. Once garlic begins to brown, add onions, carrots, and celery. Sauté until they soften and begin to brown, 7-8 minutes. Season with salt and pepper. Add the white wine to deglaze the pan. Bring to a simmer and reduce for 2-3 minutes. Remove the pan from the heat to cool for 3-5 minutes.
Meanwhile, place the tomatoes, thyme, mushroom powder and fish sauce in a vacuum bag or a Ziploc freezer bag. Pour in the sauce from the pan, season with salt and pepper and mix it all together. Add the rabbit to the bag and move down until covered by the sauce. Vacuum seal (or use the water displacement method), and cook in the 167°F (75°C) water bath for 8 hours.
After cooking, you can ice bath this and reserve in the refrigerator until you're ready to finish, or proceed directly to finishing steps.
Prepare pasta according to manufacturer's directions. Cook to al-dente, drain and set aside.
Spread the ricotta out on a plate to maximize the surface area available to receive smoke. Cover with a glass bowl or cloche. Follow the directions of your smoking gun to set it up and use the included hose to pipe smoke under the dome. You can use any type of wood you want - I like applewood. Cover and let stand for 4 minutes before releasing the rest of the smoke.
Open your vacuum bag and pour the contents (minus the rabbit) into a large saucepan or Dutch oven. Reduce over medium-high heat until some of the liquid evaporates and it reaches a thicker consistency (8-10 minutes). Taste for seasoning and add salt and pepper as needed.
Meanwhile, shred all of the meat from the rabbit.
Just before serving, remove the sauce from the heat and mix in the rabbit meat. You can add as much or as little as you want to reach your desired meat to sauce ratio, and reserve the leftover meat for other uses (it makes great tacos!).
To serve, plate the cavatelli, then the rabbit sugo, and top with smoked ricotta.
