Onion Tart

A deeply caramelized, savory tart layered with herbs and a drizzle of aged balsamic — the kind of dish that makes you feel like you're in a tiny French kitchen.

Ingredients

• 1 sheet of puff pastry, defrosted (I love Dufour Kitchen)

• 1½ tbsp olive oil

• 1½ tbsp butter

• 7 onions (a mix of yellow and red)

• 4 thyme sprigs

• 3 tbsp Madeira

• Salt

• 1 small egg, for egg wash

• 1½ cups mixed herbs (celery leaves, fennel fronds, tarragon, oregano)

• 1 tbsp aged thick balsamic

• Maldon salt

Instructions

1. Prep the Pastry
   Roll out the puff pastry onto a parchment-lined baking sheet. Use a fork to gently poke holes all over to prevent over-puffing. Refrigerate until needed.

2. Caramelize the Onions
   Cut off the stem ends of the onions, leaving the root intact. Halve them through the root and slice into half-moons.
   In a wide pan over medium heat, melt the olive oil and butter. Add the onions and thyme, season with salt, and cook for 45 minutes to 1 hour, stirring often, until deeply golden and soft. Adjust heat as needed to prevent burning.

3. Deglaze and Assemble
   Add the Madeira to the pan and stir to deglaze.
   Remove the pastry from the fridge and spoon the onions onto the center, leaving a ½-inch border. Brush the edges with beaten egg.

4. Bake the Tart
   Bake at 400°F for 30 minutes, until the pastry is golden and cooked through. Let cool for 5 minutes.

5. Finish and Serve
   Top with mixed herbs, drizzle with balsamic, and finish with a pinch of Maldon salt. Serve warm or at room temperature.