Place 70 g/2 ½ oz pistachios in a food processor, chop them slightly, and place in a bowl.
In the same food processor, add the rest of the pistachios and the flour and blend them completely. Once finely chopped and blended, add in the bowl with the crushed pistachios.
In a mixer bowl, add the butter and sugar and blend on medium speed until the butter is fluffy.
Add the salt and egg white and continue blending for 1 more minute.
Then, while blending, add the pistachio mixture in batches and continue blending until the mixture is homogenized.
Remove from the mixer, and make form balls of 25-30g (about 1oz), then create a dimple in the center with your finger, and place them on a baking pan lined with parchment paper.
Bake the cookies in a preheated oven at 175° C/345° F for 15-20 minutes.
Once ready, let the cookies cool slightly, fill the dimple with jam and serve.