Kumara pie

Rosemary crust

• 180 g plain flour, plus extra for dusting
• 1 sprig fresh rosemary, leaves only
• 1 pinch salt
• 1 pinch ground black pepper
• 120 g unsalted butter, chilled, cut into pieces (1 cm)
• 90 g water

Kumara filling

• 40 g walnuts
• 500 g water
• 800 g kumara, peeled and cut into pieces (2 cm)
• 2 eschalots, cut into halves
• 2 garlic cloves, peeled
• 80 g unsalted butter, cut into pieces
• 120 g milk
• 2 eggs
• ½ tsp salt
• 2 pinches ground black pepper
• 2 pinches sea salt flakes (optional)