Mix flour, sugar and salt in a medium bowl. Add in butter and cut with 2 knives or rub it in with your fingertips until the mixture looks like coarse sand. Add in the yolk and ice water and mix until a soft dough forms. Wrap the dough up with a plastic wrap and refrigerate for 30 minutes to rest.
Unwrap the dough and working quickly, roll it out with a rolling pin until it is big enough to cover a 7-inch tart pan. Transfer the dough into the tart pan, using your knuckles to gently ease the dough into the pan. If the dough tears, don't worry, use the excess dough to patch it up. Refrigerate for another 30 minutes.
Preheat the oven to 190 degrees Celsius.
Line the dough with a parchment paper and line with plenty of weights (I used green beans). Bake for 15 to 20 minutes in the middle rack (for small ovens) or lower third of the rack (for big ovens) until the sides are pale golden. Remove the weights and parchment paper and bake for another 3 to 5 minutes until the crust is golden. Set aside on a wire rack and let cool.
Almond Paste
Combine all the ingredients in a food processor and process until a smooth paste is formed. The paste can be made in advance and stored in the refrigerator until you need it - makes about 1/2 cup.
Tart
Preheat the oven to 175 degrees Celsius.
Place the Almond Paste, butter and sugar in a medium mixing bowl. Cream with an electric mixer until light and fluffy. Beat in the egg , followed by flour.
Spread the jam over the cooled tart shell and pour the tart batter over the jam, spreading the batter evenly. Sprinkle the almond slices all over the tart and bake for 35 to 40 minutes until the top is golden-brown in colour. Serve warm.