Simple Blackberry Iced Finger Buns (from scratch)

Name: Simple Blackberry Iced Finger Buns (from scratch)
Prep time: 10 min
Cook time: 10 min
Total time: 20 min
Cuisine: British
Ingredients: 1 egg (medium); 250ml (1 cup) milk; 50g (3½ tbs) butter; 1 tsp vanilla extract; 400-450g (3⅓ - 3¾ cups) spelt flour (see note 2); 7g (2¼ tsp) dried yeast (see note 3); 2 tbs sugar; ⅛ tsp nutmeg; 1 tsp salt; 200g (7 oz) icing / confectioner's sugar; 30g (1 oz) blackberries (see note 4)