Preheat oven to 350°F, rack on the middle shelf.
In the bowl of a stand mixer, or a large bowl, mix butter, brown and white sugar, eggs and vanilla extract, until combined.
In a medium bowl, stir flour, milk powder, salt, cocoa powder and instant coffee powder if using.
Mix wet ingredient mixture with dry ingredient mixture, stirring only until dough is formed. Add chocolate chips and almond slices, and stir until cookie dough is formed.
Using a cookie scoop, a spoon or your hands, shape cookie dough into balls. Place shaped dough into a lined baking sheet.
Bake cookies according to their size: big cookies (3 tbsp), about 13 minutes, medium cookies (1-2 tbsp), about 11 minutes, small cookies (½ tbsp), about 9 minutes. Bake just until the center is no longer glossy. Careful to not overbake, or the cookies won’t be fudgy.
Cookies will come out soft. Let them rest in the baking sheet for 2 minutes, then transfer them to a cooking rack.