Combine all ingredients in a small pot and whisk until well combined. Cook over low-medium heat, whisking continuously until it starts to thicken.

Once thick, use a heat-resistant spatula to scrape the bottom and sides of the pot. Mix continuously to prevent scorching. Check if the starch is cooked (should have no roughness and taste of raw starch)

Pour mixture into molds or plastic containers, then spread for even thickness. Cover with cling wrap, touching the maja to prevent skin from forming. Allow to chill at least 4 hours or overnight.