Shepherds Pie

Name: Shepherds Pie
Cuisine: European, British
Ingredients: for the sauce –; 1 tbsp coconut oil, or other fat; 1 large stalk celery, finely chopped; 2 medium carrots, grated; 1+1/2 lb ground lamb; 2 tsp Italian seasoning; 1 cup pumpkin purée; 1+1/4 cups bone broth (made without onions, garlic); generous pinch sea salt; for the mash –; 1 medium (3/4 lb) yam, cut into 1 inch chunks; 1 large (3/4 lb) white sweet potato, cut into 1 inch chunks; pinch sea salt; 1 tbsp freshly grated horseradish