Mix the butter (make sure it's not too cold to facilitate mixing), sugar, eggs, and vanilla. Aim for a creamy dough with small lumps.

Sift the flour together with the baking powder.

Gradually combine the mixture from the first step with the flour. Aim for a sticky and firm dough.

Add the chocolate chips and walnuts, and mix well.

Flour one or two baking sheets (first with butter, then flour). You have two options: roll out the entire dough and use a cookie cutter, or use a spoon to place small portions directly on the sheet. I recommend the latter for soft-centered cookies with crispy edges.

Preheat the oven to 392°F (200°C). Place the sheets in the oven and bake until the cookies can be easily lifted and are not burnt, just lightly golden. This takes about 15 to 20 minutes depending on the thickness and material of the sheet.

Remove the sheet from the oven, let cool, and then remove the cookies.