Potato-mushroom pot pie

Julian wanted to go out on Sunday for lunch. How many times do I need to tell him that I don't like going out...unless on top of Rome for a 17 Euro Martini.

Recipe adapted from Giallo Zafferano
time: 30 min preparation +2 hrs cooking

ingredients
for crust

• 300 g (2 cups) flour
• 150 g (10 Tablespoons) butter cold and diced
• 105 ml (2/5 cup) beer; I used Paulaner room temperature

for filling

• 500 g (1 lb) potatoes, peeled and chopped
• 500 g (1 lb) white mushrooms, chopped
• 350 g (12 oz) celery stalks, chopped
• 2 medium carrots, chopped
• 1 medium onion, chopped
• 1 cup red lentils
• 3 Tablespoons olive oil
• 1/2 teaspoon dry thyme
• 3/4 teaspoon salt

for finishing: 1 egg lightly whisked + a couple of Tablespoons of water

instructions

1. Prepare crust: in a food processor with a steal blade, blend flour with butter till sandy. Pour in beer, blend till mass forms (a couple of pulses). Take the mix in a bowl and quickly form a solid mass with your hands. Cover with a plastic wrap and put it in the fridge for 30-40 min. Meanwhile...
2. Prepare filling: In a large pot, heat oil. Add onions, celery and carrots. Saute for 5 minutes. Add potatoes and mushrooms. Add thyme and half of salt. Cover and cook on low heat for about 30 min, stirring a couple of times. Add a little water if necessary. In a small pot, bring 2 cups of water to boil, throw in lentils and cook them on low heat for 7 minutes. Add lentils to the vegetables, add salt. Set it aside to cool a bit. Meanwhile...
3. Turn oven on 200C/400F (static function). Butter and line with parchment paper a baking form. 
4. Take the dough out of the fridge, cut it in half. Roll the first half to fit your form, transfer it onto the form. Put it in the hot oven for 20 min. Take it out. 
5. Apply the filling forming a smooth peak. Roll the other half of dough and cover the vegetables. Close around the edges and make a hole in the middle. Brush it with the egg mix. Place it in the hot oven for about 40 minutes till golden.

notes

• to roll out something close to an oval shape, start with a round piece of dough and roll out (away from you) turning the dough after every move (roll); no additional flour necessary, or just a touch
• I used 28cm/11inch tart baking form
• in order for the bottom crust not to puff and break during the pre-baking, I applied dry beans on a piece on parchment paper to hold it down
• the crust is very light and delicate
• lentils turn into a thick sauce that holds all the veggies together
• pot pie is a nice idea to clean up your fridge from unused articles before Monday comes
• a fantastic dish for a big family gathering.