Nostalgic Fall Apple Puff Pastry Tart

1. Preheat oven to 350°F (175°C).
2. **Prepare the Streusel Topping:** In a bowl, combine the first 1/4 cup brown sugar, 2 tablespoons granulated sugar, 1 teaspoon cinnamon, 3 tablespoons flour, and 1/4 cup oatmeal. Mix until a crumbly paste forms. Set aside.
3. **Prepare the Apple Filling:** Cube both the Gala and Granny Smith apples.
4. In a saucepan, brown 4 tablespoons of butter over medium heat.
5. Add the cubed apples, the second 1/4 cup brown sugar, vanilla, and a pinch of salt to the saucepan. Cook until the apples are tender, then remove from heat.
6. **Assemble the Tart:** Lay the two sheets of puff pastry on a baking sheet lined with parchment paper.
7. Evenly spread the cooked apple mixture over the puff pastry sheets.
8. Crumble the prepared streusel topping over the apple mixture.
9. **Bake:** Bake in the preheated oven for 30 minutes, or until the pastry is golden brown and the streusel is crisp.
10. Once baked, remove from oven, top with caramel sauce, and enjoy warm.