A mashed potato dough forms the base and sides of this savory mushroom tart. Cook the mushroom filling until excess moisture is gone before assembling, then finish the baked tart with grated cheese.
Recipe Details
- Pan: 22 cm round pan with a removable base
- Oven: 180°C (356°F)
- Covered bake: about 40–50 minutes, then uncover to melt and brown the cheese
Ingredients
Potato Dough
- 500 g potatoes
- 30 g butter
- 50 ml milk
- 1 egg, lightly beaten
- 1 teaspoon salt
- 150 g flour
Filling and Topping
- 1 onion, finely chopped
- 1 carrot, grated
- 500 g mushrooms, sliced
- Olive oil or another cooking oil, for sautéing
- Salt and black pepper, to taste
- 150 g grated cheese
- A little butter or oil, for the pan
How to Make Potato Crust Mushroom Tart
Make the potato dough
Boil the peeled, cubed potatoes until very soft, drain thoroughly and mash. Mix in the butter and milk. Let the mash cool enough not to scramble the egg, then stir in the beaten egg, salt and sifted flour until smooth.
Cook the onion and carrot
Heat a little oil in a skillet. Soften the onion, then add the carrot and a pinch of salt. Cook for another 2 minutes and set aside.
Cook the mushrooms
Sauté the sliced mushrooms with a little oil, salt and pepper until golden and excess liquid has evaporated. Work in batches if needed.
Form and fill the tart
Heat the oven to 180°C (356°F). Lightly grease the base of a 22 cm removable-base pan and line its sides with foil as in the original method. Spread the potato dough across the base and up the sides. Add half the mushrooms, then the onion and carrot, then the remaining mushrooms.
Bake covered
Cover with foil and bake for about 40–50 minutes, until the potato dough is set and cooked through. Open the foil carefully to avoid steam; the egg-containing base should reach at least 160°F (71°C).
Add cheese and rest
Remove the top foil, sprinkle with the grated cheese and return to the oven until melted and lightly browned. Let the tart rest before releasing the pan ring and cutting.
Tips and Common Mistakes
- Drain the potatoes well so the dough does not become watery.
- Cook off mushroom liquid before filling the crust.
- The filling can be moist but should not have a loose sauce.
- Cool the mash slightly before adding the raw egg.
- A short rest after baking helps the tart hold its shape.
Storage and Make-Ahead Tips
Refrigerate leftovers within 2 hours in a covered container and use within 3–4 days. Reheat slices to 165°F (74°C). For make-ahead work, prepare and chill the cooked filling separately, then assemble before baking.
Frequently Asked Questions
Is the crust made from pastry?
No. It is a dough of mashed potatoes, butter, milk, egg and flour.
Why is the tart watery?
Poorly drained potatoes or mushrooms that still contain cooking liquid can make it wet. Drain and sauté thoroughly.
When does the cheese go on?
After the covered baking stage. Remove the top foil, add cheese and bake until it melts and browns lightly.