01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - Roll out the puff pastry onto the prepared sheet, folding the edges inward to create a 1-inch border. Prick the base with a fork.
03 - Bake the pastry for 10 minutes until slightly golden. Remove from the oven and gently press down any puffed areas.
04 - In a large bowl, whisk together eggs, milk, cream, Dijon mustard, salt, pepper, and smoked paprika until smooth.
05 - Scatter cooked bacon (or mushrooms), spinach, tomatoes, and spring onions evenly over the pastry base. Sprinkle with cheddar cheese.
06 - Pour the egg mixture gently over the fillings, spreading evenly. Return to the oven and bake for 25 minutes, or until the center is just set and the top is golden.
07 - Cool for 5–10 minutes. Garnish with chopped chives, slice, and serve warm.