Preheat the oven to 400*F, 180*C FAN, 200*C static, or Gas Mark 6.

In a bowl, add all the dry ingredients: the sifted all-purpose flour, baking powder, and salt, and mix together.

In a separate larger bowl, add all the wet ingredients: the melted unsalted butter, eggs, sugar, food coloring [if using it], milk, and lemon zest and mix well together.

Start adding the dry ingredients to the wet ones, three or four tablespoons at a time, mixing in between. As soon as it's all mixed well, stop mixing [overmixing may cause the muffins to be too dense].

Add the pistachios and mixed nuts to the food processor and chop until you achieve a coarse powder.

Add the nut mixture to the muffins batter and mix until well incorporated, without overmixing.

Add the paper liners to the muffin tin and share the muffins batter evenly, until each liner is ⅔ to ¾ full.

Place the muffins on the middle shelf in the oven and bake for approximately 18 minutes, depending on the oven.

Check that the muffins are ready using a cake tester or when a toothpick inserted in the center comes out clean or with moist crumbs, but no batter.

Once ready, remove the pistachio muffins from the oven and put the tin on a wire rack to cool down for 10 minutes.

After 10 minutes, remove the cupcakes from the tin and allow the muffins to cool completely on the rack. This will stop the moisture from settling at the bottom of the cupcake liners, making them greasy.

To decorate the pistachio muffins, roughly chop the remaining pistachio and mixed nuts, and, in a separate mixing bowl melt the milk chocolate [either bain Marie or in the microwave].

Once ready, dip the dome of the muffins in the melted chocolate and then, before it driws, dip them in the chopped pistachios and mixed nuts.

Your green pistachio muffins are ready to be served and enjoyed!