Blanch the peaches in boiling water for 1 minute. This will not only make them easier to peel but also keep their fresh, summery color. Dump them in a colander and run it under cold water. When cool enough to handle, peel the skins off the peaches with a paring knife, leaving the flesh intact. Cut the peaches in half and discard the pits, and then cut the peaches into chunks; you should have 6 cups. Squeeze the halved lemon over the fruit to prevent it from browning.
Put the peaches in a large stainless steel pot, along with the sugar and the 1/2 cup of lemon juice. Break the rosemary sprigs in half to release the oils, put them in a piece of cheesecloth, and tie it closed. (When you cook this in the cheesecloth, youâ€™ll have the rosemary flavor without the needles.) Toss the rosemary sachet into the pot and bring the fruit to a gentle simmer. Cook and stir with a wooden spoon until the fruit begins to soften and break down to a pulp, about 45 minutes. As it simmers, skim the foam off the top so you have a nice, clear product. Fish out the rosemary bag and stir in the pectin. Turn the heat up and boil for 1 minute, stirring constantly. Remove from the heat, stir in the butter to smooth out the jam, and allow it to cool.
Preheat the oven to 400Â°F. Sift together the flour, sugar, salt, baking powder, and baking soda. Using 2 forks or a pastry blender, cut in the shortening to coat the pieces with the flour. The mixture should look like coarse crumbs. Make a well in the center and add the buttermilk. Cool your hands by running them under cold water, then use your fingers to fold everything together quickly to form a dough. The shortening in the dough should be as cold as possible. Hands at 98Â°F. will begin to melt the fat and the biscuits will not rise as high.
Turn the dough out on a floured surface and, again, think coolâ€”donâ€™t use the counter next to the preheated oven. Roll the dough out to 1 inch thick; then cut out the biscuits using a floured 2-inch round cutter or an inverted glass. Lay the biscuits on an ungreased cookie sheet and brush the tops with buttermilk. Bake for 20 to 25 minutes, until the biscuits have risen and are golden.
Edited: October 9th, 2009