Step 1Heat the oven to 400 degrees.
Step 2Into a large bowl, sift together the flour, 1 tablespoon sugar, baking powder and salt. Cut in 3 tablespoons of the butter with a pastry blender. Stir in the milk to make a soft dough. Do not overmix it.
Step 3In a saucepan, mix together the remaining one-half cup of sugar and the cornstarch. Gradually stir in the boiling water. Bring the mixture to a boil, then simmer for 1 minute.
Step 4Stir in the peaches and pour the mixture into a 9-inch-square baking dish. Dot with the remaining butter and sprinkle with cinnamon.
Step 5Drop the topping by heaping tablespoons over the top of the fruit. Bake until the top is crisp and browned, about 30 to 35 minutes. Serve warm with cream or ice cream.