To make the pastry, blitz the flour, sugar almonds and a pinch of salt in a food processor for a few seconds, Add the butter and pulse again until the mixture resembles bread crumbs. Add the egg yolk and amaretto and blend until the mixture forms a ball. (If it doesn’t, see if the mixture holds together when you squeeze it—if not, add a couple spoonfuls of cold water and blitz again.) Diana suggests shaping the dough into a salami shape and refrigerating for at least two hours, then slicing the dough thinly to line your tart pan. I just pressed the mixture, which resembled fresh bread crumbs, into the bottom and up the sides of a 9-inch tart pan with a removable bottom. Put it into the freezer while you make the frangipane and slice the fruit. And preheat your oven to 350?F.
To make the frangipane, beat the butter and sugar until light; beat in the egg and amaretto or vanilla, then the ground almonds and flour. Toss the apricot wedges or halves with the sugar.
Spread the frangipane over the chilled crust—it will look like not much, but will puff up around the fruit. Arrange the apricots overtop, fitting them snugly—the fruit will shrink a bit as it cooks. Bake for 30 minutes, then reduce the oven temperature to 300?F and sprinkle the top with the almonds and some icing sugar, then return to the oven for 35-45 minutes, until golden and set. Let cool, and dust with more icing sugar before serving. Serves 8 (or more).