Place one back on the lightly floured bench and return the other half, in the bag, to the fridge. Remove the pastry from the fridge and cut in half.
When ready to bake, preheat the oven to 190C fan-forced (210C conventional) and line 2 large oven trays with baking paper. Press to form a flattened disc, then seal the bag and refrigerate for at least 2 hours (or up to 2 days). Knead gently for just a few seconds to form a smooth ball, then place in a recyclable plastic bag. Add the sour cream mixture and pulse about a dozen times until the pastry just begins to come together, then tip it out onto a lightly floured kitchen bench. Add the butter and pulse about 20 times until the butter is in small pieces and the mixture resembles coarse crumbs. Place flour, cheddar cheese, 25g of the pecorino, salt and pepper in the bowl of a food processor and pulse a few times to combine. 25g pecorino (or parmesan) cheese, coarsely grated, plus extra 10g, finely grated for sprinkling on topġ tsp freshly cracked black pepper, plus extra for sprinklingġ50g unsalted butter, cold, cut into cubesĬombine the sour cream, egg yolk, mustard, olive oil and lemon juice in a small bowl and whisk together until smooth.
