Process the plain flour, half the caster sugar and 100g of the butter in a food processor until mixture resembles breadcrumbs. Add 1 egg yolk and 1 tablespoon cold water and process until dough just clings together, adding a little more water if necessary. Turn dough out onto a lightly floured surface and knead for 30 seconds. Shape into a disc and cover with cling film. Refrigerate for 30 minutes.
Preheat oven to 200 C / Gas 6. Using electric beaters, beat the remaining butter, caster sugar and yolk until light and fluffy. Stir in the ground almonds and self-raising flour.
Roll pastry between 2 sheets of baking paper into a 26cm round. Remove top layer of paper and place remaining piece with pastry on a large baking tray. Spread almond mixture over pastry, leaving a 2cm border. Arrange the pear, in a fan shape, over the almond mixture. Brush the pear with the melted butter. Fold in pastry edge to make a border.
Bake tart for 30-35 minutes or until pastry and filling are golden and cooked. Dust with combined icing sugar and cinnamon. Serve warm or at room temperature.