Cut the pumpkin and peeled parsnips into cubes. Sauté together with the garlic in the heated butter. Pour in the vegetable stock and milk, cook in a closed saucepan at low temperature for about 30 minutes until soft. In between, check whether there is still enough liquid.
Mash the pumpkin, parsnips and garlic with the potato masher, adding a little milk if necessary. Season to taste and serve sprinkled with pumpkin seeds.