How to make cookies with powdered milk and chocolate

• Mix butter with sugar.
  200 g butter, 200 g sugar
  
• Dissolve baking soda and baking powder in a teaspoon of water.
  1/4 teaspoon baking soda, 0.5 teaspoon baking powder, 1 teaspoon water
• Add the egg and egg yolk to the butter mixture - mix briefly.
  
• Mix the flour with powdered milk and salt.
  300 g wheat flour, 75 g full-fat powdered milk, 1/4 teaspoon salt
  
• Add the dissolved baking soda and baking powder to the butter.
  
• Add the flour with powdered milk in portions and mix briefly.
  
• Add the chopped chocolate and chopped nuts - mix with a spoon.
  200 g chocolate, 120 g nuts
  
• Line two large baking sheets with parchment paper.
• Scoop portions of dough with a teaspoon and roll them into balls in your hands, roughly the size of a ping-pong ball.
  
• Arrange the cookies on the baking sheet, leaving space between them - if you want flatter cookies, you can gently flatten them with your palm.
• Bake at 160 degrees (fan-assisted mode) for about 15-20 minutes - after about 10 minutes you can swap the baking sheets to ensure the cookies are more evenly baked - if you are baking unflattened balls, bake them longer - about 20 minutes.
• After baking, cool - immediately after baking, the cookies may still be slightly soft, but they will become crispier after cooling.