Pour 1 L of lukewarm water into a large mixing bowl. Whisk in 150 g of powdered milk until fully dissolved.

Whisk 125 g of plain yogurt, 100 ml of unsweetened condensed milk, and 30 g of sugar into the milk mixture. Mix until smooth.

Cover the bowl and keep the yogurt mixture at about 40–43 °C until set. Let it ferment for about 6 to 8 hours.

Place the set yogurt in the refrigerator. Chill it for at least 120 minutes.

Put 300 g of dry degue semolina in a second large mixing bowl. Pour in 300 ml of hot water gradually while stirring.

Cover the semolina and let it absorb the water for 10 minutes. Fluff the grains with a spoon.

Stir 20 g of butter and 1/2 teaspoon of ground nutmeg into the warm semolina. Mix until the butter melts and coats the grains.

Fold 50 g of raisins into the semolina if using them. Let the mixture cool completely.

Stir 100 to 150 g of sweetened condensed milk and 1 teaspoon of vanilla extract into the chilled yogurt. Mix until evenly flavored.

Add the cooled semolina mixture to the flavored yogurt. Stir gently until the thiakry is evenly combined.

Divide the thiakry among 6 serving bowls. Serve very cold.