Preheat the oven to 400°F (200°C). Lightly grease the sides of a 9-inch tart pan with a removable bottom and place a disc of wax paper on the base. If you prefer to serve this tart on the tart pan base, do not use the wax paper.
Sift the confectioners’ sugar and flour into a bowl and stir in the almond meal and lemon zest. Whisk the egg whites for 30 seconds, until just frothy, and add to the dry ingredients with the warm melted butter. Mix until smooth.
Pour the mixture into the prepared pan. Arrange the slices of pear on top and sprinkle with the slivered almonds.
Bake in the oven for 15 minutes, then turn down the heat to 350°F (180°C) and cook for a further 10 minutes, or until risen and a pale golden color. The filling should feel firm to the touch in the center.
Allow to sit in the pan for a few minutes before turning out onto a wire rack. Dust with confectioners’ sugar to serve.
This is delicious with softly whipped cream.
Instead of pears, I sometimes use 4 oz raspberries or blackberries (either fresh or frozen) for the topping. Alternatively, I use 2 oz pine nuts instead of fruit. You can also make this with 4 oz peach or nectarine slices, which is particularly nice in the summer!