Preheat the oven to 350°F. Line an 8 inch round baking pan with parchment. Spray oil (lightly) on the pan and on the parchment paper. Keep aside.
In a large mixing bowl (or stand mixer bowl) add all the wet ingredients like yogurt, rasmalai milk, oil, and sugar and whisk until sugar is completely dissolved and the mixture is smooth.
Sift the dry ingredients, all-purpose flour, baking powder, baking soda, salt, and cardamom powder into the wet mixture.
Gently fold the dry mixture into the wet until everything is well combined and smooth (do not over-mix).
Pour the batter into the lined baking pan. Bake at 350°F for 20-25 mins or until a toothpick inserted at the center of the cake comes out clean.
Remove from oven and let it stand in the pan for 5-10 mins after which transfer it onto a wire rack to cool completely.
Transfer the cooled cake back to the baking pan. Using a toothpick or skewer, poke holes all over the cake.
Pour half cup of the rasmalai milk over the cake. Spread with a brush or spoon to make sure it spreads evenly all over the cake.
Cover the cake with cling wrap and refrigerate for 1-2 hours or overnight so the cake can soak up all the milk.