1. Combine the squash and garlic in a steamer set over boiling water. Cover and steam until soft.
2. Transfer to a bowl and mash with a fork. Add the mustard, cheese, and 1 tsp oil. Mash until well mixed.
3. Brush a small skillet with the remaining 1/4 tsp oil. Heat over medium heat. Add the pumpkin seeds. Cook, stirring occasionally, until toasted. Season with salt and pepper. Transfer to a paper towel, then crush in a mortar or blender. Fold into the squash, along with the parsley, just before serving with toasts.