Pour flour into a large mixing bowl. Add chilled and chopped margarine into the flour and using a pastry cutter, cut the margarine into the flour mixture until you have pea sized pieces and mixture is crumbly. If you don't have a pastry cutter, a fork or your hands work great.
Mix in the sour cream until combined throughout. On a piece of plastic wrap, place the ball of dough, wrap and chill in the refrigerator.
While the dough is chilling, fill a large pot with just enough water to hold all of the peaches and bring to a boil. Gently place the peaches in the boiling water and boil until skins are starting to peal off and peaches are softened, anywhere from 30 seconds to a few minutes depending on ripeness.
Remove the peaches and on a cutting board, remove the skins and slice the peaches. Place the sliced peaches into a large mixing bowl and mix in 1 tbsp sugar and almond extract. For added sweetness, add more sugar, if desired. Mix in 2 tsp corn starch into the peaches. Since the peaches are still warm, the corn starch will mix evenly. If you would like a thicker filling, add more corn starch.
Set the oven to 350° F. Remove and unwrap the chilled dough, and place on a lightly floured surgace. The dough will be very sticky so be sure to have plently of flour around and on top of the dough. Using a floured rolling pin, roll out the dough to a little over 1/4 inch thickness. Using your serving dish of choice (pie dish, 8 inch x 8 inch pan, 10 inch x 6 inch), place enough dough to cover the bottom and sides of the serving dish, reserving just enough to cover the top with strips or however you would like. Feel free to add more dough to places that appear thinner or where openings appear. Using a pizza slicer, you can cut the excess around the edges of the dish while also using it to cut strips for the top. Create your own designs with strips, fully cover the top, or make cookie cutter shapes to place on top.
Place the cobber in the middle rack of the oven and bake for 40-45 minutes, until slightly golden on top. The key is to not overbake this cobbler. Place on a cooling rack and enjoy warm with a scoop of vanilla ice cream.