First, preheat the oven to 375 degrees Fahrenheit. Add the sliced peaches, cornstarch, 1/2 a cup of sugar, and lemon juice to a medium bowl. Stir to combine.
Meanwhile, prepare the Bisquick topping. Rinse out and dry the same medium bowl before adding the baking mix, remaining sugar, milk, and butter. Stir until just combined.
Drop spoonfuls of the batter onto the peaches, and use the back of the spoon to push down and submerge the topping gently. Bake for another 15 minutes until the peach cobbler is golden on top.