Blend flour, salt and tablespoon of sugar together in a large bowl, then add cold butter, and cut into the flour with a pastry blender or knife.
When the butter is in pea-sized pieces, add the ice water and blend with a wooden spoon. Add a bit more water if the pastry seems too dry to stick together, but don't add more than another tablespoon, as the einkorn flour doesn't absorb water as readily as regular wheat flour.
Press together the pastry into a ball with your hands, press into a disk, wrap in a piece of parchment paper, and place in the fridge while you get the peach filling ready.
Preheat the oven to 400°F.
To easily remove peach skins, blanch the peaches in boiling water for two minutes, then immerse in cold water. Peel off the skins with your fingers, then slice the peaches into a bowl and stir in the sugar, flour and lemon juice.
Take the pastry out of the fridge and roll out on a piece of parchment paper to a circle approximately 14 inches in diameter. You can either leave it on the parchment and transfer to a baking sheet as is, or turn into a pie dish and peel off the parchment paper.
Spoon the peaches on top of the pastry (if you are using the flat baking sheet, leave a 2 inch border of pastry around the edge) and then gently fold the edges of the pastry over the peach filling.
Place on the center rack in the oven, and bake for about 45-55 minutes; until the crust is golden and the peaches are starting to caramelize on top. Serve warm with softly whipped cream.
*Oxalate content is medium per serving (6.95 mg) if pie is cut into six servings, made with six peaches.