Preheat oven to 400 degrees.

In a large bowl, fold the peaches, 1/4 c. each white and brown sugars, cinnamon, nutmeg, lemon juice and cornstarch until all ingredients are well combined.

Pour fruit mixture into a 9 x 13 inch baking dish.

Place in preheated oven and bake for 10 minutes.

While peaches are in the oven, mix together all the cake topping ingredients, except the boiling water, to a medium bowl.

Use a pastry blender to cut the batter into the dry ingredients until the mixture looks like coarse meal.

Pour in the boiling water and stir until just the mixture comes together and is mixed through.

After the peaches have baked for 10 minutes, pull from the oven and drop large spoonfuls of the dough topping over the peaches.

Evenly sprinkle the top of the dough with the 3 Tablespoons of sugar.

Place the baking dish on a cookie sheet, and bake for another 30 minutes or until topping is golden and peaches are tender.