Cook butter in a pan with medium heat. It will be sizzle and bubbly from the water content. After the moisture and the sound of the sizzle are gone, wait for 1-2 minutes until the milk solids from the butter turn brown and turn off the heat. Don't let the pan unattended or you will end up with burnt butter instead of brown butter.
Transfer it on a heatproof bowl. Set aside and let cool.
Sift flour and baking soda to a bowl. Set aside.
After the browned butter is cooled, whisk browned butter, brown sugar, white sugar, egg, vanilla, and salt with a mixer for about 2-3 minutes until mixture is fluffy.
Add 1/3 of the flour mixture and whisk with a mixer until just combined. Add the rest and whisk again until combined.
Add chocolate chips and almonds and stir with a spatula until combined. Leave both a little for decoration.
Divide every 2 tablespoons dough for each cookie. Add 3 chocolate chips and 3 sliced almonds on top every cookie dough from the rest chocolate chips and almonds. Every cookie will be pretty. Put them on a parchment paper and refrigerate for 6 hours. (1-48 hour is ideal)
Preheat oven to 350ºF or 175°C. Line baking sheet with parchment paper. Put the cookie dough balls 2 inches from each other so they will not stick when baked.
Bake for 10-12 minutes until golden brown. Cool for 2-5 minutes before removing to wire racks to cool completely.