Add the starter and water to the mixer bowl and mix.
Add flour, yeast, tangzhong and milk powder. Knead briefly until there are no traces of dry flour. Cover with a wet cloth and set aside for 15-20 minutes.
Add honey or maple syrup, egg and salt and knead until the dough is smooth and elastic, about 10 minutes. Cover with a damp kitchen towel and set aside in a warm place until it doubles in size (about an hour).
Transfer the risen dough out onto a flour- dusted board or countertop. Divide it into 10 equal parts and roll each piece into a tight ball. Cover the balls with a kitchen towel and set aside for a while.
Meanwhile, press the garlic through a press or chop it finely and put it in a bowl. Add soft butter and mix everything well.
Lightly dust the pastry board or countertop with flour. Take the first dough ball and gently roll it into an ellipse. Spread the long "pancake" with the butter and garlic mixture. Start at the short end and roll along the long side, creating a croissant shape. Place on a baking tray lined with baking paper.Continue in same manner with the remaining dough balls. Cover the croissants with a damp kitchen towel and leave to rise for about 30 minutes. Meanwhile, preheat the oven to 220℃. With a fork, beat the egg with a tablespoon of water or milk to make the eggwash.
When the croissants are nicely puffed, brush them well with the eggwash and transfer into the oven. Bake for about 20-25 minutes until golden brown.Remove from the oven and cool on a rack. If you want a stronger garlicky kick, you can spread the still warm croissants with an additional mixture of butter, garlic and parsley.