Oat and Cashew Pasties

Filling

• 150 g rolled oats
• water, for soaking
• 100 g cashew nuts
• 15 g fresh parsley
• 150 g onions, quartered
• 250 g tinned chopped tomatoes
• 50 g red peppers, cut in pieces
• 50 g olive oil
• 4 garlic cloves
• 2 tsp fine sea salt
• 3 large eggs
• 1 tsp dried oregano

Dough

• 800 g water
• 1 tsp fine sea salt
• 600 g potatoes, red skin, peeled, cut in pieces (2 cm)
• 240 g unsalted butter, soft
  of 240 g margarine
• 600 g strong white bread flour, plus extra for dusting
• 3 egg yolks, beaten, for brushing