Preheat oven to 350 degrees Fahrenheit. Spray or grease a 9x13 inch pan and set aside.
Prepare oat topping- in a medium-sized bowl, mix together oats, flour, brown sugar, cinnamon, and salt. Then add the cubed butter and mix together with a pastry cutter, a fork, or by using your hands until you have pea-sized pieces. Set aside in the refrigerator until ready to use.
Prepare filling- in a small bowl, mix flour, white sugar, and cinnamon and set aside.
Peel, core, and thinly slice the apples and pears around 1/4 inch in thickness and place them in a large bowl. Toss with lemon juice to keep from browning too quickly. Now add the cinnamon sugar filling mixture and stir together until all of the apples and pears are covered. Pour into the baking pan.
Drizzle the caramel over the top of the apples and pears. Sprinkle the streusel oat topping over the top of the apples and pears.
Bake uncovered for 45 minutes or until fruit is soft and topping is crispy and slightly golden brown. Allow to cool at least 15 minutes before serving. Enjoy!