Cut the apple into 2 halves and finely dice half of the apple. Take yogurt in a bowl. Add powdered sugar into it. Now add cinnamon powder and diced apple. Mix well and keep it in fridge for atleast 45 minutes. The shrikhand is ready.
Grease a baking sheet pan or line it with parchment paper. Arrange walnuts on it so that they are close and placed together. Caramelize sugar in a pan.
For caramelizing sugar, add sugar in a even layer to a heavy bottomed saucepan. As you heat the sugar, it will release its water and caramelize.
Heat the sugar over a moderate heat.
Watch the caramel closely as it heats - it should begin to liquify around the edges, turning from a clear liquid to a golden brown color.
Do not add spoon into the sugar but move the pan in a circular way for even heating.
Once the sugar melts completely and turns brown, take the pan off the heat immediately and pour it over the walnuts. Allow it to settle and cool.
After 15 minutes, pound the candied walnuts into small pieces. Keep it aside.
Cut and slice the remaining half apple into half moon shape. Use these sliced apples for garnishing later while serving,
Serve shrikhand in a bowl. Arrange the sliced apples on the sides of the bowl in circular manner and sprinkle candied walnuts over it. Serve it cold.