If your yolks are from store-bought salted eggs, rinse them gently to remove excess whites. Steam them for 8–10 minutes or bake them at 160°C (320°F) for 8 minutes until slightly firm and lightly oily. Let them cool while you make the cake.

Preheat your oven to 160°C (320°F) and line a 12-cup muffin tin with cupcake liners.

Separate the egg yolks and whites into two bowls. In one bowl, beat the egg yolks with the milk, melted butter (cooled slightly), and vanilla.

Sift together the all-purpose flour and cornstarch, then mix into the yolk mixture until smooth.

In another bowl, beat the egg whites with lemon juice until foamy, then gradually add the sugar. Continue whipping until soft peaks form.

Fold the whipped egg whites gently into the yolk-flour batter in batches, being careful not to deflate the airiness.

Divide the batter evenly into the 12 cupcake liners and gently tap the tray to remove large air bubbles.

Bake at 160°C (320°F) for about 20–22 minutes, or until a toothpick comes out clean. Let them cool before decorating.

In a mixing bowl, add the egg yolks and sugar. Whisk until pale and slightly thickened.

Slowly drizzle in the oil while whisking continuously. It’s a lot like making mayonnaise—slow and steady wins the race. The mixture should emulsify into a glossy, thick sauce.

If it’s too runny, chill it briefly in the fridge before piping or spooning onto your cakes.

Once the cakes are cool: Spoon or pipe a generous swirl of the sốt dầu trứng on top of each cupcake.

Place one or two salted egg yolks on each cake. Then you can sprinkle pork floss (ruốc) around the salted egg yolks for extra texture and umami.