Preheat your oven to 375 degrees Fahrenheit.
Add the flour, sugar, baking powder, and salt to a large bowl and combine them with a wire whisk.
Zest the two lemons over the bowl of the dry ingredients using a lemon zester, then add the roughly chopped pistachios and whisk the mixture into the bowl with the other dry ingredients.
In a separate bowl, combine the eggs, milk, lemon juice and oil and whisk them together with a fork. Dump this into the dry ingredients and combine the wet and the dry ingredients together gently with a rubber spatula. Be careful not to over mix! Stop combining as soon as you see the flour disappear.
Divide the thick batter evenly between 18 muffin cups lined with paper liners. Bake the muffins at 375 degrees Fahrenheit for 19-22 minutes or until the tops begin to brown just slightly and the muffins spring back when you touch them gently.
While the lemon pistachio muffins are cooling, prepare the glaze by adding the powdered sugar and lemon juice to a small bowl and whisking until smooth.
When the muffins are completely cool, drizzle a small amount of the glaze over each muffin, sprinkle some chopped pistachios over the top, and serve!