Crust: Using a stand mixer or handheld electric whisk, cream the butter, sugar and vanilla together until lightened. By hand, gently mix in the flour and almonds. Press the resulting crumbs into a 25cm loose-bottomed tin (or several smaller ones if you have decided to make individual servings).Custard: Using a stand mixer or handheld electric whisk, cream together the cream cheese and sugar.
Add the egg and vanilla and mix to completely combine.
Pour into the prepared (uncooked) crust.Apples: Slice the apples as thinly as possible - a mandoline is good for this. Toss gently in the sugar, cinnamon and lemon. Leave to soften for 10 minutes or so. Arrange in a layer on top of the custard. Start by laying overlapping apple slices all the way round the edge. Next create the 'rose' - arrange the slices in a spiral, standing the apple slices a little on their edge, until the centre hole is completely filled in. Save the smallest, thinnest pieces for the very centre as they will have to bend the most. Cover the tart with tin foil and bake in a preheated oven set at 190c for 30 minutes (this step helps soften the apples).
Remove the foil and bake for 15-25 minutes longer, until the custard is puffed and the apple edges are lightly browned.Glaze: When you take the tin foil off the apple tart, start making the glaze. Melt the sugar in a small saucepan over medium-high heat and cook until rich and golden.
Add the butter and salt and stir to combine.
Add the cream and continue to cook, stirring constantly, until the ingredients have formed a smooth, unified caramel. When the tart looks nearly ready, remove it from the oven and brush with the glaze. Return to the oven and cook for a further few minutes until the glaze is gently bubbling. Cool to room temperature. Can be kept in the fridge for several days - store in the baking tin and wrap well.
