- Season rabbit generously with salt and pepper. Refrigerate for 24 hours.
- Place rabbit in large pot and cover with cold water. Bring the water to simmer over medium heat, skimming any unwanted foam and fat from the top.
- Add 2 cups onions, ½ cup leeks, 2 cups celery, thyme, bay leaves, and peppercorns. Cover and simmer 1 hour until rabbit is very tender.
- Carefully remove rabbit and let cool. Pick meat from bones. Strain cooking liquid. Keeping it warm, reserve and discard any solids.
- In another heavy-bottom pot, melt butter over medium-low heat. Add flour and stir until thick, 5–8 minutes. Add remaining vegetables and cook 10 minutes or until tender. Add garlic and cook for another 2 minutes.
- Slowly add reserved broth and allow to simmer 20 minutes or until broth has slightly thickened. Season with salt and pepper and add hot sauce.
- Add rabbit meat. Add dumplins (recipe below) and cook additional 20 minutes. Finish with chopped parsley, tarragon, and chives.
- Mix flour and salt together in bowl. Cut butter into flour mixture with fingertips until it resembles small peas.
- Add buttermilk ¼ cup at a time and stir until ball of dough just begins to form, being careful not to over-mix. Roll out dough onto floured surface, about ¼-inch thick.
- With sharp knife, cut dough into rectangles or squares. Place dumplins on floured pan, dividing layers with parchment paper. Let dumplins rest in refrigerator at least 30 minutes before adding to stew.