Empadinhas de Palmito

I will never forget my first encounter with palmito (hearts of palm).  It was during my first trip to Brasilia where my dear friend, Erik (who was also my very first Brazilian friend) took me to what he claimed was the best place in the city of Brasilia, the capital of Brazil, to get a pastel, a fried pastry that can have any number of fillings.
Having sampled almost every sort of pastel the previous week whilst eating my way through Belo Horizonte in Minas Gerais, I decided to try a filling I hadn't yet sampled. That is when I fell in love at first bite with palmito.  A revelation!
  I still haven't learned to make pastéís (the plural of pastel) yet.  But I did learn to make the wonderful little pies, empadinhas (em-pah-jeen-yahs) with the flakiest crust imaginable...  They also come filled with everything you could ever imagine... The most popular kind is a chicken filling which I will try and post on here at a later date.  In the meantime, try these out!
Note:  I use empadinha forms which I purchased in Brazil to make mine but you can also use mini muffin tins.  They work just fine.

Empadinhas de Palmito

Dough

600 grams regular unbleached flour
1 tablespoon salt
300 grams unsalted butter, softened
3 large egg yolks
50 ml water

Filling

2 tablespoons extra virgin olive oil
1 medium onion, finely diced
2 cloves garlic, minced
2 medium roma tomatoes, skinned, deseeded and chopped fine
1 14-oz can hearts of palm, drained well and chopped
salt and pepper to taste
1 tablespoon chopped flat leaf parsley
1 tablespoon chopped scallions
1 8-oz tub mascarpone cheese
3 egg yolks, beaten, for brushing on the tops

To make the dough, sift the flour and salt together.  Work the butter into the dough with your fingers.  Beat the yolks into the water, add the mixture to the flour and mix well with your hands.  Divide the dough into two balls and wrap each in plastic and refrigerate for at least 45 min.

To make the filling, saute the onion in olive oil on medium heat until translucent.  Add garlic and saute about 30 seconds.  Add the tomatoes and saute until the oil floats free, about 20 minutes.  Add the hearts of palm and cook for about 10 minutes.  Add seasonings to taste.  Let cool and fold in parsley and scallions.  Set aside.

To assemble, cut strips of dough from the ball and press them into the forms trying to make them somewhat thin.  (Don't even think of trying to roll this dough out like you would regular pie dough.)
Place a spoonful of the filling in each form and top with another spoonful of mascarpone cheese.
To make the lids, put a piece of dough on a cutting board and spread in each direction using your thumb.  Place it over the empadinha and trim the edges with a small sharp knife.  Press the top dough into where the dough in the forms meets the edge.  Brush with egg yolk.
Place the finished forms on a baking sheet and bake for about 25 minutes or more depending on the size of your forms.
Remove from the oven and let rest a few minutes before running the blade of a sharp knife around the inside of the edges to release the pies.
Serve warm or let cool to room temperature and store in plastic bags.  Reheat just before serving.