Method

• 1.
  For the pastry, place flour in a large bowl with a pinch of salt. Using your fingertips, rub the extra 30g chilled butter into the flour until a rough crumb. Mixing with a butter knife, gradually add 100ml chilled water, adding more if necessary, until a dough forms. Turn dough onto a lightly floured surface and roll into a 20cm x 10cm rectangle. Grate half of the frozen butter over the bottom two thirds of the dough. Fold the top third of dough into the middle and the bottom third on top of that, as if folding a letter. Turn the folded dough 90 degrees and roll into a rectangle again. Repeat with the remaining frozen butter, and do another letter fold. Roll out the dough one more time, fold into thirds and wrap in plastic wrap or a beeswax wrap. Chill for 30 minutes before using. Meanwhile, preheat oven to 200°C.
• 2.
  Place rosé, sugar and vanilla in an ovenproof 27cm frypan over high heat and bring to the boil, stirring to dissolve the sugar. Cook for 8-10 minutes until thick like a caramel. Add butter and cook until melted and combined. Remove from heat.
• 3.
  Trim rhubarb into lengths to fit across the pan and arrange in an even layer over the caramel. Roll the chilled pastry out into a 28cm circle and gently place over the rhubarb, tucking the edges of the pastry under within the frypan. Prick the top with a fork and place pan on a baking tray, and bake for 45 minutes or until the pastry is puffed and golden. Allow to sit for 5 minutes, then carefully invert onto a serving plate. Serve warm with ice cream.