Sift the flour, baking powder, salt and 2 tablespoons of sugar into a large bowl. Cut in butter by pinching between your fingers until the mixture resembles coarse polenta. Press into the bottom and up the sides of a 20x30cm baking dish.
Place the peach halves cut side up on top of the crust in a nice pattern. Mix together the remaining sugar and cinnamon; sprinkle over the peach halves.
Bake for 15 minutes in the preheated oven. While the peaches are baking whisk together the egg yolks and cream in a medium bowl. Pour over the peaches after the 15 minutes are up.
Reduce the oven's temperature to 180 degrees C. Return the dish to the oven and bake for 30 to 40 minutes, until golden brown.