【For Sponge Cake】Sift cake flour. Put unsalted butter, milk and honey in a small bowl; set aside. Prepare hot water to warm egg mixture (low heat). Preheat an oven to 190℃ / 374 F.

Beat egg lightly until becomes watery. Add granulated sugar and mix lightly. Warm it in hot water until it reaches body temperature.

Take the egg mixture out of the hot water. Warm the milk, butter and honey in the hot water (extremely low heat); set aside. Whisk the egg mixture with a hand mixer on high speed. The batter should fall slowly forming a ribbon that will hold it's shape for a moment.

Whisk it on low speed for 2 min to make bubbles smaller and same size. Add the flour in 3 parts while sifting each time. Fold it about 20 times after each addition. Mix the cake batter of around the inside of the bowl and fold about 10 times.

Take the warm milk mixture (milk, butter, honey) out of the hot water. Take a small amount of the batter and stir it into the warm milk mixture. Mix thoroughly. Add it back and fold 20-30 times. Please mix the batter of bottom sometimes.

Drop the bowl lightly about 10 times to remove large bubbles. Pour it into a baking tray and flatten it. Drop the tray lightly several times.

Bake it at 170℃ (338F) for 15 min. After baked, drop the tray to prevent shrinkage. Take the cake out of the tray. Let it cool. When cooled, peel off the parchment paper.

Cut out 2 circles from the sponge sheet with a 18 cm (7'') mousse ring. Cut out the upper right corner and the lower left corner. Place the first layer of sponge cake in the ring. Set aside the other circle sponge. Cut the stalk of the strawberries (about 20 pieces) off so they have a flat base. Cut about 10 strawberries vertically in half.

Arrange them around the inside of the mold with the cut side facing out. Arrange remaining strawberries in a circle. Let it sit in a fridge.

【For White Chocolate Mousse】Whisk heavy cream while cooling with ice water until it becomes heavy. Let it sit in a fridge. Soak gelatin in the water; set aside. You should put water first to prevent the gelatin from becoming uneven. Cut white chocolate into small pieces.

Put the chocolate in a bowl. Put the bowl in hot water (300 ml boiling water + 300ml water, same ratio, 50℃/ 122 F) and melt the chocolate. When all melted, add 100ml boiling water to the hot water. Leave the bowl in hot water.

Mix egg yolk and granulated sugar with a whipper until it becomes whitish. Add vanilla oil and mix. Put milk and condensed milk in a pot.

Warm the milk on low heat for 2 min while stirring. Add the milk to the egg mixture while stirring. Pour it back in the pot.

Cook it on low heat while stirring. Cook it until the mixture gets thickened lightly. Turn off the heat and add the gelatin to melt thoroughly.

Add the melted chocolate and mix well. Strain it and crush the lumps of chocolate and smooth it. Place it in a large bowl of ice water. Cool it down for 2 min stirring. Take it out of the ice water.

Add the chilled heavy cream in 3 parts. Mix well each time. Add rum and mix well. Mousse is ready.

【Assembling】Take the mousse ring out of the fridge. Put the mousse in the mold without gaps and flatten.

Top with the remaining sponge. Let it sit in a fridge for 3 hours to harden the mousse. And then cut the top of sponge cake to flatten.

Warm the ring with hot towel and lift the ring gently.

【For Topping】Put white chocolate and milk in a small bowl. Microwave them to melt the chocolate (600W, about 30 sec). Cool down as it is for 2-3 min. Apply the chocolate on the top of the cake. Let it cool in a fridge for 15 min.

Make jelly for coating strawberries. Put granulated sugar and agar in a small bowl and mix well; set aside. Put 250ml water in a pot and bring to a boil. Turn down the heat a little after boiling. Add the sugar and agar in 4 parts. Melt it thoroughly each time. After all melted, continue to heat it for a min.

Turn off the heat. Let it cool as it is for 7-8 min. Dip strawberries (about 15 pieces) in it. This jelly will solidify at room temperature.

Take the mousse cake out of the fridge. Sprinkle powdered sugar. Top with the glossy strawberries. Whip heavy cream and granulated sugar and pipe small round shapes around the strawberries. Top with 5-6 blueberries and mint. It' all done!