Warm up the milk in the microwave for few seconds just until it's warm, no need to be boiling hot. Cut the dried longan into small pieces. Soak the dried longan in the warm milk for about 30 minutes while you prepare other things
Toast the walnuts on a dry pan without any oil over medium-low heat until they are fragrant and nutty. Chop them into small pieces and set aside
Preheat oven to 400 F (200 C) for conventional oven, 380 F (190 C) for convection oven. Line your 12-well muffin pan with cupcake liners
Prepare the batter:
Combine all the dry ingredients and set aside. In a mixing bowl, whisk the eggs and sugar until the sugar melts, add the melted butter, and vanilla and the milk you use to soak the dried longan. Whisk to combined
Add the flour mixture, soaked longan, and walnut pieces. Use a spatula to fold until just combined and you no longer see any loose pockets of flour. It is important not to overmix the batter or the muffins will turn out dense
Scoop the muffin batter into each cup, filling it about 3/4 full. Add the walnut pieces on top and sprinkle with some turbinado sugar
Baking:
Bake in the preheated oven, middle rack for 15-17 minutes or until the top is dry to touch and spring back when you touch lightly. A toothpick inserted should come out pretty clean with some crumbs, but nothing should be wet. DO NOT overbake the muffins or they will be dry and tough
Let them cool down in the pan for 5 minutes (Do not skip this step). Then transfer to a cooling rack to let them cool down completely
Storing:
Once the muffins have cooled down completely, store them in an air-tight container or in a zipper bag, push all the air out and seal. They stay fresh at room temperature for 2-3 days.
To freeze them, I usually individually wrap each muffin with a cling wrap and them seal them in a freezer bag and keep in the freezer for up to one month. To serve, simply thaw at room temperature before serving