In a large mixing bowl, add the softened butter. Using an electric mixer, beat the butter on medium speed for approximately 3 minutes, or until it becomes light in color and creamy in texture.

Pour the sweetened condensed milk into the creamed butter. Beat on medium speed for 2 minutes, ensuring the mixture is smooth and fully combined. If adding an extract for flavor, incorporate it at this stage, using no more than 2 teaspoons. Scrape down the sides of the bowl and beat again briefly to ensure uniform consistency.

Add the all-purpose flour and baking powder to the mixture. Beat on low speed just until the dry ingredients are fully incorporated. Avoid overmixing to maintain a tender texture. If incorporating optional additions such as chocolate chips or dried fruit, fold them in at this stage, limiting additions to no more than 1 cup total.

Using a cookie scoop, portion the dough into evenly sized mounds and place them onto a parchment paper-lined baking sheet. Leave at least 2 inches of space between each portion to allow for slight spreading during baking.

Preheat the oven to 320°F (160°C). Bake the cookies for 12 minutes, or until the bottoms are lightly golden while the tops remain pale.

Remove the baking sheet from the oven and allow the cookies to cool on the pan for 5 minutes. Transfer the cookies to a wire rack to cool completely. Once fully cooled, use a fine sieve to generously dust the cookies with confectioner’s sugar before serving or storing.