Pre heat the oven to 180C/Gas Mark 4.

Grease a 20cm round cake tin.

Top and tail the oranges, then slice away the skin.

Grate the zest from your oranges and reserve.

Thinly slice the oranges, and arrange them in the bottom of your cake tin.

Make the syrup - put the brown sugar, lemon juice, tequila and liqueur into a small pan.

Stir until sugar melts, bubbles and the consistency thickens.

Pour into the tin over the oranges.

Mix together the reserved orange zest, polenta and flour in a bowl.

In a separate bowl, beat together the butter and caster sugar.

Beat in the eggs, one a time, until combined.

Finally mix in the Greek yoghurt.

Gently fold the the dry ingredients into the wet, and pour the batter into the tin.

Pop into the oven.

The cake should take 45 minutes to bake - test by inserting a skewer into the cake - if it is clean when removed, it's done.

Let the cake cool for a while in the pan (to allow the syrup to cool).

Run a sharp knife around the edge to loosen it, then turn it out, upside down onto a plate.

Slice and enjoy!