2 cups flour
pinch of baking soda
1/2 cup + 1 tsp butter
1/2 cup + 1/8 cup sugar
grated rind of 1/2 lemon
2 egg yolks
2 Tbsp sour cream
3/4 cup jam, I used apricot
1/2 cup ground walnuts [optional]
• Preheat the oven to 350F.
• In a large mixing bowl rub together the flour and the cold butter until it becomes a homogenous crumble.
• Add the sugar, grated lemon rind, egg yolks and the sour cream and kneed it into smooth dough.
• Now cut the dough into two equal parts.
• [If you are making a jam lattice bar, use 2/3 of the dough for the base and 1/3 for the lattice. Without the ground walnuts you will need a slightly thicker base, besides the thinner lattice will be prettier with more of the jam showing through. But adding walnuts alters things a bit and for that dividing the dough in equal parts is perfectly fine.]
• Roll out the base and lay it in a square parchment lined baking pan.
• Let the dough come up a little way around the sides. This will contain the jam.
• Spread the jam to the edge and sprinkle with the ground walnuts if using.
• Cut the remaining dough in half, and on a lightly floured surface roll them out with floured hands to two 1/2 inch ropes.
• Cut one of the ropes up into pieces to suit the size of the pan.
• Divide the ropes diagonally over the filling.
• Repeat with the second rope to make a lattice top.
• Brush the top lightly with some of the leftover egg white and place the pan in the preheated oven.
• Bake until the filling is hot and the crust is lightly browned.
• Let the bars cool slightly before cutting.
• For exact squares let the bars cool completely before slicing.