Lightly grease a baking tray and the inside of the cake ring (or grease the baking tin if using). Place the ring on the tray and set aside.
Cream the butter and sugar until light and fluffy.
Add the oil and vanilla extract and mix well until fully combined.
Add the egg slowly beating well before the next addition, scraping down the bowl as you go.
Sift the flour, baking powder and salt three times to ensure it’s evenly combined.
Fold the flour into the butter mixture.
Divide the dough in half (approx. 215g each). Wrap one half in cling film and put in the freezer for about 20 minutes to firm up.
Using your fingers, press the other half of the dough into the base of the cake ring as evenly as possible. Press the dough up the side of the ring a little to form a small ridge. This will act as a barrier to prevent the jam from oozing out.
Spread the jam over the base dough then put the tart in the fridge to cool for 20 minutes while the other half of the dough is cooling.
Preheat the oven to 150C.
Once the second half of dough has firmed up, remove from the freezer and grate the dough over the jam layer using a coarse grater size. Gently rearrange the grated dough to even it out if necessary.
Bake the tart for approximately 50 mins or until it has just started to colour.
Remove from the oven. Remove the ring, dust with icing sugar.
Best served warm and with a dollop of crème fraiche.
Keyword crumble topping, easy jam tart, farfel tart