Preheat oven to 180c/gas 4.Grease a 7 inch sandwich tin.
In a large mixing bowl rub the lard or butter in to the flour and salt . The mixture should resemble fine breadcrumbs.
Mix in the egg and add the water, mix until a stiff dough is formed.
Turn dough out onto a lightly dusted flour board . Knead the dough until a smooth flexible dough is formed.
Roll out the pastry so that it will line the sandwich tin.
Put greaseproof paper onto the pastry and fill with baking beans.
Bake for 10 mins. Remove the paper and beans and return to the oven for a further 5 mins .
Peel and slice the onions.
In a large frying pan heat the olive oil and fry the onions over a low heat until they are soft. Turn the heat up and brown the onions. Add the sugar and cook for a few minutes .Add the vinegar and stir in. Remove from the heat.
Put onions into pastry case and top with slices of Goats Cheese.
Bake the tart for 20 mins until the cheese has melted and starts to go brown.Serve and enjoy.
