Preheat your oven to 150°C (300°F) and line an 8" by 5" (20cm by 13cm) loaf pan with parchment paper. You’ll also need a deep baking dish in which you can place your loaf pan and enough hot water to fill the baking dish 1 inch up (water bath baking method).

In a bowl, sift the flour and salt. Set aside.

In a saucepan, heat the milk and butter until the butter has melted and the mixture just starts simmering. Pour the mixture into the bowl with dry ingredients and whisk until smooth and homogenous in consistency.

Add egg yolks one at a time and vanilla extract, then whisk until well incorporated.

In the bowl of a stand mixer fitted with a whisk attachment (or use a hand mixer and a bowl), add the egg whites and lemon juice. Whip on medium-low until the mixture is foamy. Then, gradually add the sugar while whipping.

When all sugar is in, switch the speed to medium-high and whip to medium peaks. Do not overwhip to stiff peaks!

When done, fold ⅓ of the egg white mixture into the egg yolk mixture until well combined.

Pour the egg yolk mixture into the rest of the egg whites and gently fold using a rubber spatula.

Pour the mixture into the prepared loaf pan and tap it a couple of times against a flat surface to force the large air bubbles out.

Place the pan in a larger baking dish and transfer the construction into the oven. Pour hot water into the baking dish, close the oven, and bake the cake for 45-50 minutes or until the top is golden-brown and springy to the touch. The toothpick inserted into the center should come out clean.

Remove from the oven and let it rest in the pan for 10 minutes. Then, pull out by holding the parchment paper ends and place on a flat surface to cool down completely before serving.