Strain the Yogurt: If your yogurt is not already very thick, line a fine-mesh sieve with cheesecloth or a clean paper coffee filter. Place it over a bowl. Spoon the yogurt into the sieve, cover with plastic wrap, and refrigerate for at least 4 hours, or preferably overnight. This will drain the whey, leaving you with a thick, cream-cheese-like consistency.

Prepare the Fruits: Wash your chosen fruits thoroughly and pat them completely dry with kitchen towels. Any surface moisture is the enemy of a crisp sugar shell. For fruits like hawthorn or apples, hull or core them and cut into bite-sized, skewerable pieces. If using grapes leave them whole but ensure they are dry. Take a small knife and make a shallow hollow or cut a small pocket in each piece of fruit—this is where the yogurt will go.

Assemble the Skewers: Using a small spoon or knife, fill the hollow in each piece of fruit with a dollop of your strained, thick yogurt. Thread 3-4 pieces of yogurt-filled fruit onto each bamboo skewer, leaving a little space between them.

Cook the Sugar Syrup: In a heavy-bottomed, light-colored saucepan (so you can see the color change), combine the granulated sugar and water. Stir gently just once or twice to moisten all the sugar. Place the pan over medium-high heat.

The Crucial Waiting Game: From this point on, do not stir. Stirring can cause the syrup to crystallize. Instead, gently swirl the pan occasionally. Let the mixture come to a boil. It will first form large, clear bubbles. Continue cooking until the bubbles become much smaller, more uniform, and densely packed. The syrup will thicken slightly. This should take about 10-15 minutes.

Test for the "Hard Crack" Stage: Have a small bowl of ice water ready. Dip the tip of a fork or chopstick into the syrup, then immediately dip it into the ice water. Wait a few seconds, then try to snap the sugar off the utensil. If it makes a clean, sharp snap and is completely hard, it's ready. If it's chewy or bends, continue cooking for another minute and test again.

Dip and Coat: Once the syrup is ready, reduce the heat to the lowest setting to keep it fluid. Working quickly and carefully, lift a skewer and tilt the saucepan and swirl the skewer in the syrup, coating the yogurt-filled fruit evenly and thinly. Let the excess drip off for just a second.

Add the Milk Skin (Optional): Immediately after dipping, while the sugar is still hot and sticky, gently press the coated fruit skewer onto the pieces of milk skin. The warm sugar will act as glue. Repeat with the remaining skewers.

Serve and Enjoy: Allow the Tanghulu to set for 2-3 minutes until the sugar shell is completely cool and hardened. Enjoy immediately for the ultimate contrast between the warm, crisp shell and the cool, creamy fruit inside.