Preheat oven to 325 degrees convection. Butter two 13x9 pans, then fit a half sheet of parchment crosswise into each. Butter bottom of parchment.

Whisk flour, baking powder, salt, and cinnamon in small bowl. In small saucepan, heat butter with milk just until butter is melted. Set aside.

Use stand mixer with whisk to beat eggs until foamy. Gradually add sugar, then whip at high speed until thick and glossy, about 5 minutes.

At low speed, slowly add butter-milk mixture and 2 teaspoons vanilla. Mix just until combined. Add flour mixture in 3 additions.

Divide batter between prepared pans. Bake until cake springs back when lightly touched, about 30 minutes. Cool cake completely, then refrigerate until cold.

Meanwhile, using stand mixer, beat 2 cups cream with golden syrup and 2 teaspoons vanilla until stiff peaks form. Chill.

Meanwhile, mix evaporated milk, condensed milk, 1 cup cream, and 1 teaspoon vanilla. Chill.

Assemble. Remove cake from one pan. Use parchment as a sling to flip it over back into the same pan. Remove parchment. Poke holes in cake and drizzle one-third of milk/cream mix over. Chill for 30 minutes.

Spread half of beaten cream over cake layer. Invert second cake layer on top of cream, then remove parchment. Chill for 30 minutes.

Poke holes in top of cake, then drizzle over ⅓ of milk/cream mixture (save remaining ⅓ for optional garnish). Chill for 30 minutes.

Spread with remaining beaten cream. Sprinkle top with additional cinnamon. Refrigerate at least 2 hours before serving.

note: do not use all of milk mixture in cake. It’s too soggy.