Shallot tart

Instructions

1. Preheat the oven to 200°C (400°F). Roll out the puff pastry on a lightly floured surface to fit your tart pan. Line the tart pan with the pastry, trimming any excess. Prick the base with a fork and chill in the refrigerator for 15 minutes.
2. In a large skillet, heat olive oil and butter over medium heat. Add the shallots, cut side down, and cook for 10 minutes until they start to caramelize.
3. Sprinkle sugar over the shallots, and cook for an additional 5 minutes, allowing them to caramelize further.
4. Add balsamic vinegar and thyme leaves, stir gently, and season with salt and pepper. Cook for another 2-3 minutes until the liquid is reduced and syrupy.
5. Remove the tart shell from the refrigerator. Spread Dijon mustard evenly over the base.
6. Arrange the caramelized shallots, cut side down, over the mustard in a single layer.
7. Brush the edges of the pastry with beaten egg to ensure a golden crust.
8. Bake in the preheated oven for 25-30 minutes, or until the pastry is golden and puffed.
9. Remove from the oven and let cool for a few minutes before slicing and serving.