Preheat the oven to 175C (350F) and line 2 baking sheets with parchment paper.

In a bowl, combine the flour, baking soda, and salt.

In the bowl of a stand mixer (or use a mixing bowl and a hand mixer or a metal whisk), add the butter and white sugar. Beat on medium for 1-2 minutes until it resembles a homogenous paste, scraping the sides and the bottom of the bowl in the middle of the process. DO NOT beat the butter until fluffy.

Then, add the egg and beat until fully incorporated and the mixture has emulsified.

Add the condensed milk and beat until incorporated.

Add the dry mixture and mix on low just until no dry ingredients are left.

Scoop out 14 cookie dough balls (approximately 35g each) on a baking sheet, leaving a 2” (5cm) distance in between.

Bake in two batches for 12-13 minutes, or until the cookies have spread, and become golden on the edges.

Remove from the oven and drop the tray on a flat surface to deflate the cookies. Let them cool down for 10 minutes on the tray. After, transfer onto a cooling rack to cool down completely.