In a small saucepan, combine rolled oats, 1 cup of water, chia seeds, and 1 teaspoon of vanilla extract. Cook over medium heat for 3–4 minutes, stirring frequently to prevent sticking. The oats should start to thicken and become creamy. Continue cooking until you reach your desired consistency, typically around 5–7 minutes.

Reduce the heat to low and stir in ½ cup of full-fat coconut milk, adjusting with additional water if needed for a smoother texture. Let the mixture simmer gently for about 2–3 minutes, stirring occasionally until fully combined.

In another small saucepan, heat ½ cup of coconut milk over medium-low heat. Mix 1 tablespoon of cornstarch with a small amount of water to create a slurry, then gradually add it to the warm coconut milk. Stir in 2 tablespoons of coconut sugar, and heat for 3–5 minutes until the mixture thickens.

To serve your Mango Sticky Rice Oatmeal, ladle the creamy oatmeal into bowls. Top generously with freshly sliced mango pieces, drizzle over the thick coconut sauce, and sprinkle with a pinch of black sesame seeds.