Heat oven to 180C/160C fan/gas 4.
Lightly oil 2 x 18cm sandwich cake tins
(preferably loose-bottomed) and line the
bases with baking parchment. Tip the
flour, baking powder, caster sugar and
ground almonds into a large mixing bowl,
then make a well in the centre. Beat the
eggs in a bowl, then stir in the yogurt
and vanilla. Pour this mixture, along with
the melted butter and oil, into the dry
mixture (step 1) and stir briefly together with
a large metal spoon until well combined.
Divide the mixture evenly between
the 2 tins (step 2) and level the tops. Bake
both cakes, side by side, for 20 mins
until risen and beginning to come away
slightly from the edges of the tins.
Remove the cakes from the oven and
loosen the sides with a round-bladed
knife. Let the cakes cool briefly in the
tins, then turn them out. If the tins are
loose-bottomed, an easy way is to sit
the tin on an upturned jam jar and let the
outer ring of the tin drop down (step 3). Peel
off the lining paper and sit the cakes on
a wire rack. Leave until completely cold.
Put one of the cakes on a serving plate
and spread over the conserve (step 4). Put the
other cake on top and sift over the icing
sugar, or make a pattern (see tip below).