Stand mixer or hand mixer Essential for beating egg whites and whipping cream to stiff peaks.
Mixing bowls Several for separating eggs, whipping, and mixing.
9x13-inch cake pan or two 8-inch round cake pans Depends on whether you want a single-layer tray or a multi-layer round cake.
saucepan To steep the Thai tea.
Strainer or cheesecloth For straining Thai tea leaves if you're using loose tea.
Offset spatula For smooth frosting and layering.
Wire Rack For cooling the sponge completely before soaking.
Ingredients
For the Sponge Cake
1cupall-purpose flour
1tspbaking powder
1/4tspsalt
5large eggsseparated
1cupgranulated sugardivided
1/3cupwhole milk
1tspvanilla extract
For the Thai Tea Milk Soak
2Thai tea bags or 2 tablespoons Thai tea leaveslook for a brand like Pantai
1cupboiling water
1/2cupsweetened condensed milk
1/2cupevaporated milk
1/2cupwhole milk
1tbspsugaroptional, adjust to taste
For the Whipped Cream Topping
1 1/2cupsheavy cream
1/4cuppowdered sugar
1/2tspvanilla extract
Optional Garnishes
Crushed Thai tea cookies or tea cake cookies
Toasted coconut flakes
Mini dollops of Thai tea whipped cream or condensed milk drizzle
Instructions
Make the Sponge Cake
Preheat your oven to 350°F (175°C). Grease and flour your baking pan(s). In a medium bowl, whisk together flour, baking powder, and salt.
In another large bowl, beat the egg yolks with half the sugar (1/2 cup) until pale and thick. Stir in milk and vanilla. Fold in the flour mixture gently.
In a separate clean bowl, whip the egg whites until soft peaks form. Gradually add the remaining 1/2 cup sugar and continue beating until stiff peaks form. Gently fold the whipped egg whites into the yolk batter in three parts, careful not to deflate the airiness.
Pour the batter into the prepared pan(s) and bake for about 25–30 minutes, or until a toothpick inserted comes out clean. Let the cake cool completely on a wire rack.
Prepare the Thai Tea Milk Soak
While the cake bakes, steep your Thai tea in 1 cup boiling water for 5–10 minutes. Strain out the tea leaves or remove the bags. Combine the steeped tea with sweetened condensed milk, evaporated milk, and whole milk. Stir until fully blended and chill until ready to use.
Soak the Cake
Once the sponge cake is fully cooled, use a fork or skewer to poke holes all over the surface. Slowly pour the Thai tea milk mixture over the cake, letting it absorb a bit at a time. It will look overly saturated at first—don’t worry, that’s the point.
If you're doing a layer cake, split the cake horizontally and soak both layers individually before stacking.
Whip the Cream Topping
In a cold bowl, whip heavy cream, powdered sugar, and vanilla extract until stiff peaks form. Chill if not using immediately.
Assemble the Cake
If you’re going with a layered version, place one soaked layer down, spread a generous amount of whipped cream on top, then add the second layer and repeat. Finish by coating the entire cake with whipped cream and smoothing it with an offset spatula.
Garnish and Chill
Top with crushed cookies, toasted coconut, or a swirl of condensed milk. Let the cake chill in the fridge for at least 1 hour (ideally 2+) before serving.