Start by gathering all your ingredients. Preheat your oven to 350°F (175°C) so it’s ready to go when you finish assembling the crisps. Prepare a muffin tin or small baking dish for portioning—this will give each serving an individual home.

In a mixing bowl, combine the brown sugar, melted butter, and flour. Stir until it begins to resemble wet sand. Now, add in the chopped walnuts, oats, ground cinnamon, and cardamom. Mix everything thoroughly. This crumble needs to have texture, so make sure it's chunky enough for that satisfying bite.

In a separate bowl, toss the finely diced apple with the brown sugar, fresh lemon juice, flour, and ground cinnamon. Make sure each piece of apple is coated; this ensures even sweetness and flavor distribution when baked.

Now, layer your apple mixture into the bottom of your muffin tins (or small baking dishes). Distribute the crumble topping generously over the apples. You want a nice thick layer—no skimping!

Place the muffin tin in the preheated oven. Bake for about 15-20 minutes or until the apples are bubbly and the topping turns a golden brown. Your kitchen will smell heavenly at this point, so hang tight!

Once finished, allow the apple crisps to cool for a few minutes. If you’re planning to freeze them, let them cool completely. Wrap each portion tightly in plastic wrap or foil, and then place them in a freezer-safe container. These treats can be stored in the freezer for up to three months.