Heat oven to 400°F. Use muffin cups to line muffin tins.
For The Crumb Topping:
In a skillet, toast pumpkin seeds over med-high heat until they begin to "pop" and brown and spots (about 3 minutes). Transfer to a small bowl and toss with the oats, coconut palm sugar, flour and cinnamon.
Using your fingers, work the butter into the dry ingredients until evenly mixed and a crumbly consistency in reached.
For The Muffins:
In a 3-quart saucepan, combine the pumpkin puree and pumpkin pie spice. Cook over medium heat 5 to 6 minutes once it starts to steam, stirring constantly, to evaporate some of the liquid and condense flavor.
Remove from heat and mix in butter, maple syrup, coconut palm sugar, and cream cheese until smooth. Whisk in eggs and vanilla.
In a mixing bowl, combine the flour, walnuts, baking powder, baking soda, and salt. Add the pumpkin puree to the dry ingredients and stir until flour is just mixed it.
Fill muffin tins 3/4 full; sprinkle streusel topping over each one. Bake for 16 minutes or until toothpick inserted in the center, comes out clean.
Cool on wire racks in the pans for 5 minutes. Remove muffins from pans and continue to cool on racks until cooled completely. Store loosely covered.
These muffins freeze well, though the topping will only be crisp just after baking.How to make your own pumpkin pie spice:Mix 3 tablespoons ground cinnamon, 2 teaspoons ground ginger, 2 teaspoons ground nutmeg, 1 ½ teaspoons ground allspice and 1 ½ teaspoons ground cloves.