1. Preheat the oven to 180°C (350°F), Gas mark 4. Butter the sides of the cake tin and line the base with greaseproof paper.
2. Remove the stalks and stones from the cherries using a cherry pitter if you have one, to keep the fruit whole, otherwise cut them in half and discard the stones. Set the cherries aside.
3. Sift the flour and cinnamon into a large bowl, add the sugar, mix together and make a well in the centre.
4. Whisk the egg, milk and melted butter together in another bowl, then pour into the dry ingredients and combine with a wooden spoon or whisk. Beat well to make a thick, smooth mixture, then spoon into the prepared tin and spread evenly. Scatter the cherries over the mixture and gently press them in with the back of a fork.
5. To make the topping, tip all the ingredients into a bowl. Rub in the butter with your fingertips to make a crumb-like mixture and scatter the topping over the cherries.
6. Bake in the oven for 30-35 minutes or until the top is lightly golden and a skewer inserted into the middle comes out clean.
7. Leave in the tin for about 10 minutes until cool enough to handle, then run a knife around the edge and remove the cake from the tin. Allow to cool on a wire rack.
8. Dust with icing sugar, if you wish, and serve.