Peel the pumpkin, cut into cubes and cook with very little water, then chill. Mix the chia seeds with the almond milk and let soak for 3 - 4 hours, possibly overnight.
Then puree all the ingredients, chia seed almond milk and pumpkin cubes with a hand blender.
Let the dessert stand a little more, fill into bowls and garnish with the roasted walnuts.