Special equipment: stand mixer, 8 1/2 by 4 1/2-inch glass loaf pan
Preheat the oven to 350 degrees F.
Butter and lightly flour the loaf pan.
In a food processor, add 1 1/2 cups of the pistachios and pulse until finely ground. Remove them to a large bowl and mix in the flour, poppy seeds, baking powder and 1/2 teaspoon of salt.
In the bowl of a stand mixer fitted with the paddle attachment, cream the 3 tablespoons of butter and the sugar on medium speed for 2 minutes. Add the egg and continue to beat until the mixture turns pale yellow and ribbons form. Mix in the milk and the zest until incorporated. Gently stir the mixture into the dry ingredients to combine.
Pour into the loaf pan and smooth the top. Dot with the remaining 1/4 cup of whole pistachios and sprinkle with a pinch of sea salt. Bake until lightly golden and toothpick inserted in center comes out clean, about 1 hour 10 minutes. Remove the bread from the pan and cool on a wire rack, about 10 minutes. Slice and serve warm or at room temperature with creamed honey.