Peel off the onion and garlic and, like the dates, dice finely.
Heat the oil in a pan and fry the mince in it until light brown. Add onions and garlic and fry for about 2 minutes. Stir in tomato paste and roast briefly. Add 250 ml water and the diced dates and bring to the boil. Season with salt, pepper and cinnamon.
Scrape the soft inside and seeds out of the pumpkin with a tablespoon. Grate the pulp with the skin and season with salt and pepper. Mix the grated pumpkin with 1 tablespoon butter.
Grease the baking dish with 1 tablespoon butter. Pour in the mince mixture and spread the grated pumpkin on top. Cook in the hot oven at 200 ° in the lower third of the oven for 45 minutes (convection not recommended).
Pluck the parsley leaves from the stems and roughly chop them. Sprinkle the pumpkin casserole with parsley and serve with sour cream.