1. Preheat Oven and Prepare Pan:

• Preheat your oven to 350°F (175°C).  
• Grease and flour an 8×8-inch square baking pan thoroughly. Alternatively, line the pan with parchment paper, leaving an overhang for easy lifting, and grease the parchment. Set aside.

2. Mix Wet Ingredients:

• In a large mixing bowl, whisk together the sweetened condensed milk, melted (and slightly cooled) butter, room temperature eggs, and 1 teaspoon vanilla extract until the mixture is smooth and fully combined.

3. Combine Dry Ingredients:

• In a separate medium bowl, whisk together the all-purpose flour, baking powder, and salt to ensure the leavening and salt are evenly distributed.

4. Combine Wet and Dry:

• Gradually add the dry ingredients to the wet mixture in the large bowl.
• Stir gently with a whisk or rubber spatula just until the ingredients are combined and no large streaks of flour remain. Be careful not to overmix the batter.

5. Bake the Cake:

• Pour the prepared batter into the greased (and floured/lined) 8×8-inch baking pan.
• Use a spatula to smooth the top evenly.
• Bake for 30–35 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean or with only a few moist crumbs attached.  

6. Cool the Cake:

• Remove the pan from the oven and let the cake cool in the pan on a wire rack for about 10 minutes.
• If lined with parchment, use the overhangs to lift the cake out onto the wire rack. If not lined, carefully invert the cake onto the wire rack.
• Let the cake cool completely before adding the glaze (if using).

7. Make and Apply Glaze (Optional):

• Once the cake is completely cool, make the glaze if desired.
• In a small bowl, whisk together the sifted powdered sugar, 1 tablespoon of milk, and 1/2 teaspoon vanilla extract until smooth.
• If the glaze is too thick, add more milk, just a tiny drizzle (1/2 teaspoon) at a time, until it reaches your desired drizzling consistency. If too thin, whisk in more sifted powdered sugar.
• Drizzle the glaze over the top of the cooled cake. Let the glaze set for about 15-20 minutes before slicing.

8. Serve:

• Slice the Condensed Milk Cake into squares and serve. Enjoy!