Preheat oven to 350ºF. Spray a 9 x 5-inch loaf pan with cooking spray and lightly dust with flour. (Alternatively, use 2 small aluminum disposal loaf pans). Bring butter to room temperature.
In medium bowl, mix together the dry ingredients (flour, baking soda, baking powder, cinnamon and salt). Set aside
In the bowl of a stand mixer, with the paddle attachment, beat together the softened butter and sugar until light and fluffy (about 3 minutes). Add eggs, one at a time, beating well after each addition. Add lemon zest and pumpkin puree and beat until combined.
Remove mixer bowl and add the dry ingredient mixture to the bowl. Stir in until just incorporated (don't overmix). Stir in Amaretto and milk. Fold in the nuts, reserving a handful for the topping.
Pour batter into prepared pan and bake in the center of the oven until a knife inserted into center of bread comes out clean, about 45-60 minutes.
Cool the bread in the pan for 20 minutes, then invert onto a wire rack, turn right side up and sprinkle with reserved nuts. Then let it cool completely.
If you are shipping this, wrap it securly in plastic wrap after it has cooled. Then wrap the whole thing in aluminum foil. It freezes well if not sending right away.