8small ripe pears, such as corella, halved, core removed with a melon baller150 gmcaster sugarThinlypeeled rind and juice of 2 lemons40 mllemon liqueur, such as limoncello50 gmbutter, coarsely chopped2 tbspextra-virgin olive oil40 gmnatural almonds, coarsely choppedAlmond pasta frolla60 gmnatural almonds180 gmplain flour100 gmcold butter, coarsely chopped60 gmpure icing sugar, sievedFinelygrated rind of 1 lemon1egg plus 1 egg yolk, lightly beatenAlmond cream160 ml(2/3 cup) milk3 pieceslemon rind, removed with a peeler2egg yolks110 gm(½ cup) caster sugar1½ tbspplain flour50 gmsoftened butter40 gmalmond meal20 mllemon liqueur, such as limoncello
For almond pasta frolla, process almonds and 50gm flour in a food processor until finely ground. Add butter, sugar, rind, remaining flour and a pinch of salt, process until fine crumbs form. Add egg mixture, process until mixture just comes together, turn onto a lightly floured surface, knead lightly until smooth. Wrap in plastic wrap, refrigerate to rest (1-2 hours).
Meanwhile, for almond cream, bring milk and rind to the simmer over medium-high heat. Meanwhile, whisk yolks and half the sugar in a bowl to dissolve sugar, then whisk in flour. Add milk mixture, whisk to combine, return to pan, whisking continuously until thick and smooth (2-3 minutes), then remove rind and cool completely. Beat butter and remaining sugar in an electric mixer until pale and fluffy (1-2 minutes), add almond meal, liqueur and cooled custard, set aside at room temperature.
Meanwhile, preheat oven to 160C. Place pears, cut-side up, in a roasting pan that fits pears snugly. Scatter with sugar and lemon rind, drizzle with lemon juice and liqueur and dot with butter, making sure to include one in each cavity. Drizzle with oil and roast, basting occasionally, until pears are tender and edges are golden (35-40 minutes). Keep warm.
Meanwhile, divide almond pasta frolla into eight. Working with one piece at a time, and keeping other pieces refrigerated, roll on a floured surface into 3mm-thick rounds and line eight 9cm-diameter tart tins. Divide almond cream among tarts, scatter with almonds, bake until golden (35-40 minutes). Serve warm or at room temperature with roast pears and syrup. Crostate are best eaten on day of making.