Mix flour, salt, sugar, yeast, butter, eggs, milk, and 25ml warm water until combined.
Add up to another 100ml warm water gradually until a soft dough forms.
Knead dough on a floured surface for 10 minutes until smooth and elastic.
Prove dough in an oiled bowl covered with cling film for one hour.
Preheat oven to 170°C.
Roast onion, pepper, and squash strips with olive oil on trays for 15 minutes.
Toast 50g pine nuts in a dry pan until lightly browned.
Blend toasted pine nuts, parmesan, olive oil, garlic, and basil in a food processor.
Knock back the proved dough for 20 seconds and divide into two equal portions.
Roll one half into a 32cm diameter circle and place on a baking tray.
Spread three tablespoons of pesto over the base and layer with vegetables, feta, and walnuts.
Roll out the second dough half into a 32cm circle and place over the filling.
Trim the dough to a 30cm circle and place a bowl in the centre.
Cut 16 radiating strips from the bowl, twist each twice, and point the ends.
Prove the shaped bread for 30 minutes and preheat oven to 190°C.
Brush with beaten egg, sprinkle with pine nuts, salt, and pepper, then bake for 25 minutes.