Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
Roll out the puff pastry into a 10–12 inch round (or leave rectangular for ease).
In a small bowl, mix goat cheese with chopped herbs and a drizzle of olive oil. Season with salt and pepper.
Spread the herbed goat cheese in the center of the pastry, leaving a 1.5-inch border.
Layer tomato slices and scatter corn kernels over the cheese. Season again with salt and pepper.
Fold edges of pastry over the filling, pleating as needed.
Beat the egg and brush the pastry edges with the egg wash.
Bake for 30–35 minutes, until the pastry is golden and crisp.
Let cool slightly before slicing. Serve warm or at room temperature.