- Blitz the butter and caster sugar in a food processor until smooth, scraping the bowl to ensure everything is incorporated. Add the egg, yolk and vanilla extract and blitz again until blended.
- In a separate bowl, mix the flour, polenta, baking powder and salt. Add this to the wet mixture in the processor, and mix until the dough starts to clump together. It will be a little sticky.
- Tip the dough onto a lightly floured counter. You may need floured hands to handle it. Shape 1/3 of the dough into a flat disc, wrap with cling film and chill until firm so it’s easier to handle.
- Lightly grease a 23cm tart tin with removable base or oven proof pie dish. Press the remaining dough into the tin or pie dish with your fingers pressing it evenly into the bottom and 2 - 3cm up the sides.
- If the dough is very sticky, either flour your hands or cover it with cling film to stop the dough sticking to your fingers. Refrigerate until firm (at least one hour) or freeze for about 30 minutes. Once chilled, spread the dough with the jam.
- Between two sheets of baking parchment, roll the dough disc until about 3mm thick. Use a small heart cutter to cut out as many hearts as you can. Re-roll if you need to, but the dough may need to be chilled before re-rolling so it doesn’t get too sticky.
- Arrange the hearts on the jam, starting from the outside and working into the centre. Refrigerate for another 30 minutes — to ensure the hearts keep their shape. Whilst they are chilling, preheat your oven to 190°C (170°C fan).
- Sprinkle with the granulated sugar and bake until the crust is golden brown, about 25 minutes.
- Cool on a wire rack.
This tart was inspired by a David Leibowitz recipe from his fabulou book, Ready for Dessert . Choose any flavour of jam you happen to have - I mixed rhubarb and strawberry. The dough has a lovely sandy texture from the polenta, but if you’re short on time, bought pastry will work very well indeed.