Glamorgan Sausage Roll - Lucy & Lentils

Ingredients

• 150g leeks (around 2 small leeks)
• 100g / 1 cup breadcrumbs
• 1 ½ tsp smoked paprika
• 1 ½ tsp sage
• 1 tsp mustard
• Large punch black pepper
• 2 tbsp nutritional yeast
• 250g apple sauce (unsweetened if possible)
• 1 sheet puff pastry (270g)
• ¼ cup stock (I used ½ stock cube with boiling water)
• 1 tbsp black sesame seeds