- Line a baking sheet with parchment paper. Roll out the dough into a 25-cm (10-inch) square and place on the baking sheet. Refrigerate for 15 minutes.
- In a skillet, melt half the butter and honey. Brown the endives on both sides until they are tender. Season with salt and pepper. Set aside.
- In the same skillet, brown the mushrooms and onions in the remaining butter. Season with salt and pepper. Set aside.
- With the rack in the middle position, preheat the oven to 180 °C (350 °F).
- In a bowl, blend the mustard and cream. Spread on the puff pastry.
- Scatter the mushrooms and arrange the endive, flat side up. Bake for 25 minutes or until the pastry is golden brown.
- Garnish the tart with cheese shavings. Serve as an appetizer.