Separate 4 eggs into yolks and whites, and let them come to room temperature. Preheat the oven to 350 degrees F. Line just the bottoms of 12 egg-tart or brioche molds with small circles of parchment paper. We used molds with a top diameter of 3.8". Do not grease the molds or the parchment paper.

In a large stainless steel or glass bowl, sift together 1 cup of cake flour, 1.5 tsp baking powder, 1/3 cup granulated sugar, and 1/2 teaspoon salt. Then add 4 egg yolks, 1/3 cup vegetable oil, 1/3 cup milk, 1/4 cup ube halaya, 2 tsp ube extract, and 1/2 tsp purple food coloring. Beat with an electric mixer or by hand just until smooth or well blended.

In a separate stainless steel or glass bowl, beat together 4 egg whites and 1.5 tsp cream of tartar on low speed until frothy, about 1 minute. Increase the speed to medium, and very slowly add in 1/3 cup sugar. When all the sugar is added, increase the speed to high and continue beating until stiff peaks are formed. One third at a time, fold this meringue mixture into the ube cake mixture until well combined. Distribute this batter evenly into the 12 prepared molds. We added about 1/4 cup of batter to each mold.

Bake in the preheated oven at 350 F for 15 to 20 minutes, or until a toothpick inserted into the center of the cake comes out clean.

Let the mamon cakes cool in the molds for 5 minutes. Then invert them onto a small square of parchment paper to unmold, and then transfer them top side up onto a cooling rack.

Melt 2 tbsp of unsalted butter. While the mamon cakes are still warm, brush the top of each mamon with melted butter. Serve immediately.

Mamon cakes will keep in an airtight container at room temperature for 1 to 2 days, or in the fridge for 3 to 4 days. If stored in the fridge, let them come to room temperature before serving. Enjoy!