Preheat the oven to 300 degrees F. Line two baking sheets with parchment paper.

Place the egg whites in a mixer fitted with a whisk attachment. Add the salt and cream of tartar and beat until foamy.

Add the lemon juice.

Slowly add the sugar. Beat the mixture until stiff peaks form.

Fold the ground pistachios into the egg white mixture.

Load the mixture into a pastry bag.

Pipe the cookies out onto the baking sheets.

Place a pistachio half into the middle of each cookie.

Place in the oven and bake for 25 minutes.

Remove the cookies from the oven and transfer to wire cooling racks.

Let cool completely before serving.