Arrange a rack in the middle of the oven, then preheat it to 200 °C / 400 °F. Grease two large baking sheets with butter or use a silicon mat (like Silpat). Don't use parchment paper.
make the batter
Cut the softened butter into cubes and add to a large bowl. Add the sugar, salt, lemon zest, and optionally add the vanilla paste too. Using an electric mixer or a stand mixer fitted with a whisk attachment beat the mixture until smooth. Mix for about 3 - 4 minutes at high speed. Then quickly incorporate the egg and mix until combined. Add the all-purpose flour and baking powder. Stir well using a spatula to get an even, smooth batter. Don't overwork the cookie dough.
Prepare your cookie press (or use a piping bag if you don't have a cookie press) and fill it with the cookie batter. Form desired shapes on the prepared baking sheet and place the first batch in the preheated oven. Bake for 8 - 10 minutes at 200 °C / 400 °F or until the cookies are golden-brown and crumbly. Repeat the process with the rest of the cookie dough.TipPress a small amount of cookie dough from the cookie press before shaping the cookies to release the air from the press and to get prettier cookies.
Spritz cookies with Chocolate and Pistachios
Remove the baked cookies from the oven. While they are still warm, transfer them from the baking sheet to a wire rack using a fish spatula. They will be harder to remove once they are cold. Be careful, these cookies are very crumbly when hot. Melt the chocolate in your microwave in two 20-second intervals or use a bain-marie. Add canola oil to the melted chocolate, and stir to combine. Dip the cooled cookies in chocolate and sprinkle them with chopped pistachios. Serve or store in an airtight container or cookie box for up to 14 days.