Preheat the oven to 350°F. Grease a 9x13-inch baking dish and set it aside.
Peel and chop the apples so they are about ½-inch to ¾-inch in size.
Transfer the cubed apples to a large pot and add the lemon juice, ¾ cup granulated sugar, and brown sugar.
Cook the apples over medium heat stirring until the sugars have dissolved. The apples will release a fair amount of liquid, this is normal – do not pour the liquid off.
Sprinkle ¼ cup of flour, 2 teaspoons of cinnamon, vanilla extract, and ½ teaspoon of salt over the apple mixture. Gently stir with a soft silicone spatula until the ingredients are well combined.
Continue to cook the apples for 5 minutes, stirring frequently so they don’t burn. The mixture should be thick and caramelized, and the apples should be well coated.
Transfer the apples to the prepared baking dish.
In a medium-sized bowl, whisk together the topping ingredients of flour, granulated sugar, salt, and baking powder. Add the softened butter and cinnamon and mix with a fork until the mixture looks like wet sand.
Sprinkle the topping mixture over the apple layer, pressing down and making sure to cover as many of the apples as possible.
Place the baking dish in the oven and bake it for 35 minutes or until the top is golden and the caramel is bubbling.
Remove the cobbler from the oven and let it sit for 5 minutes before serving.