First, preheat your oven to 350°F (175°C). Prepare a 3-quart baking dish by greasing it lightly with butter. This step ensures that the crisp will not stick to the dish and will give it a beautiful, golden brown finish.

Next, peel and slice the apples into wedges or chunks, depending on your preference. Placing them in a large mixing bowl, sprinkle with lemon juice and orange juice immediately to keep them from browning. Add the sugar, spices (cinnamon, nutmeg, allspice), cornstarch, and zests. Gently toss to coat the apples evenly in the mixture, ensuring every piece gets a taste of the delightful spices.

Transfer the apple mixture into the prepared baking dish, spreading them out evenly. This layer of apples will provide the base for your crisp and will caramelize beautifully during baking, enhancing the flavors with each passing minute.

In another mixing bowl, combine the flour, oats, both sugars, and sea salt. Mix them until well combined. Now, here’s the fun part! Add in the cold butter cubes. Using your fingers or a pastry cutter, work the butter into the dry mixture. Aim for a crumbly texture where the butter is evenly distributed. This will create that sought-after crunchy topping.

Sprinkle the topping generously over the apples, ensuring that every inch of filling is covered. Now it’s time for the oven! Bake for about 45 to 55 minutes or until the apples are bubbling and the topping is golden brown.

Once baked, remove the dish from the oven and let it cool for about 10 to 15 minutes. This resting period is essential. It allows the filling to set slightly, making serving easier. Scoop it warm into bowls and enjoy!