Preheat the oven to 175°C (gas mark 5-6). Lightly wet a non-stick baking sheet. Unroll the puff pastry and place it on the sheet. Brush with beaten egg yolk, prick all over with a fork, and fold the edges inward by 1 cm to form a border.
Bake for about 15 minutes until golden. If it puffs up, prick and flatten with a flexible spatula.
Sort and wash the greens and herbs. Drain well and slice into a fine chiffonade, including the chard.
In a 26 cm non-stick sauté pan, heat the olive oil with garlic and chili. Once garlic is golden, discard both. Add the chopped greens and herbs, season with salt, cover, and cook over medium heat for 3 minutes. Uncover, stir frequently for 5 minutes until water evaporates. Stir in cream, reduce, then season with pepper. Remove from heat.
Take the baked pastry from the oven. Mix the remaining egg yolk into the herb mixture. Spread over the pastry base. Peel the blood pudding, slice obliquely into 7-8 mm pieces, and arrange in a rosette pattern on top.
Return to the oven for 10-12 minutes, until the pudding crisps. Serve hot.
Bon appétit!
