Pre heat the oven to 200oC / Fan 180oC / Gas 6 and take the pastry out of the fridge.
Heat a large frying pan over a medium-low heat. Add the pine nuts and dry fry. Toss frequently for 1-2 minutes until golden then set to one side.
Put the pan back on the heat and add half the spinach. Dry fry for a couple of minutes and toss frequently until the spinach has wilted. Tip the spinach into a colander place over/in the sink. Repeat with the remaining spinach and allow to cool.
Unroll the pastry and use a 10 cm pastry cutter to cut out 6 circles. Gently press the pastry circles into the Yorkshire pudding cups and put the trays in the fridge.
Once the spinach has cooled, squeeze out the excess water and roughly chop. You should go from a large bowl of spinach to a large handful. This step is important to avoid a soggy bottom!
Pop the spinach, feta, sun dried tomatoes, pesto, eggs, thyme, zest, pepper and 30g of the pine nuts into a bowl. Mix well with a fork to break up the spinach and evenly distribute the feta.
Remove the Yorkshire pudding tray from the fridge and evenly distribute the mixture between the 6 pastry lined cups. Place on a baking tray and bake for 16-18 minutes, until the golden and the pastry is cooked.
Scatter with remaining pine nuts and serve with new potatoes and salad.
Allow any remaining tarts to cool completely before storing in an airtight container in the fridge. These will keep for a couple of days in the fridge.