Preheat oven to 350°F. Place the pumpkin in a microwave safe dish and cover with plastic wrap tightly. Microwave on high for 8 minutes. Transfer cooked pumpkin to a blender or a food processor and puree. Add the eggs, honey, coconut oil, lemon zest and cinnamon and puree until smooth.
Add the almond flour and baking powder and combine. Divide the mixture between 2 bowls. Stir the cocoa powder into the mixture in one of the bowls.
Line loaf pan (8.5 x 4.5'') with baking paper. Place alternate spoonfuls of the chocolate and pumpkin batters into the prepared pan. Bake for 40-50 minutes. Use a toothpicks to test readiness. Leave to cool in the pan before serving.