In a medium bowl, combine the pumpkin puree, chopped walnuts, sugar, cinnamon, nutmeg, ginger, and cloves. Mix thoroughly until all the spices are evenly incorporated and the mixture feels cohesive. Set aside.
Keep phyllo dough covered with a damp towel to prevent drying. Melt the unsalted butter and have a pastry brush ready.
Lay one sheet of phyllo on a clean surface and brush it with melted butter. Place a second sheet on top and brush again. Spoon a thin line of the pumpkin nut filling along one edge of the layered phyllo. Carefully roll the phyllo into a tight log, sealing edges with extra butter. Repeat until all filling and phyllo are used.
Place the rolls on a buttered baking sheet, spacing slightly. Brush tops with more melted butter. Bake at 350°F (175°C) for 25-30 minutes until crisp and golden brown.
While baking, combine honey, water, and vanilla extract in a small saucepan. Warm gently over low heat until honey melts and syrup is blended. Remove from heat and cool slightly.
Immediately drizzle warm honey syrup over baked rolls, allowing it to soak in. Sprinkle chopped pistachios on top for garnish.
Let rolls cool completely to room temperature so syrup sets. Serve with tea or coffee for a cozy treat.