For the shortbread base
- 225g unsalted butter, chilled and cut into cubes
- 2 fresh thyme sprigs, leaves picked
- 100g caster sugar
- 325g plain flour
- Icing sugar to dust
- Edible flowers to serve (optional; see tip)
For the topping
- 215g caster sugar
- 40g plain flour
- Juice 2 lemons, plus finely grated zest ½
- Juice 1 orange, plus finely grated zest ½
- 4 medium free-range eggs
You’ll also need…
- 20cm x 30cm cake tin, greased and lined with non-stick baking paper
- For the base, heat the oven to 180°C/160°C fan/gas 4. In a food processor, pulse together the butter, thyme and sugar with a pinch of salt until the mixture is creamy. Add the flour and pulse again until it just comes together to form a dough. If you don’t have a food processor, beat the ingredients in a mixing bowl using an electric mixer until creamy, then quickly beat in the flour.
- Press the dough into the lined cake tin, then chill for 30 minutes until very cold. Prick the base all over with a fork, then bake for 20-25 minutes until golden and dry.
- Mix the topping ingredients (don’t over-whisk), then immediately pour over the baked base. Return to the oven for another 20-25 minutes until just set, then leave to cool in the tin. Dust with icing sugar and scatter with edible flowers, if you like. Cut into squares or rectangles to serve.