Prepare the apple filling: Place a large frying pan over medium heat and add 30g of the butter. Once it melts and sizzles gently—you’ll hear a soft hiss—toss in the diced apples. Stir with a wooden spoon until every piece glistens with butter, about 1 minute. The apples should look glossy and start to release a faint, sweet steam.

Season the fruit: Sprinkle the brown sugar, cinnamon, nutmeg, and lemon juice over the apples. Pour in the water and stir thoroughly. The mixture will look thin and syrupy at this stage, with the sugar dissolving into a pale amber liquid.

Cook the apples: Bring the pan to a gentle bubble—small, lazy bubbles around the edges—then reduce the heat to medium-low. Let it simmer uncovered for 8 to 10 minutes, stirring occasionally. The apples will soften and the liquid will thicken into a glossy, golden sauce that coats the back of your spoon. You’ll know it’s ready when a fork slides easily into a chunk but the apple still holds its shape.

Make the crisp topping: While the apples cook, combine the oats, flour, demerara sugar, and salt in a mixing bowl. Cut the remaining 30g of cold butter into small cubes and rub it into the dry mixture with your fingertips until it resembles coarse breadcrumbs. The texture should feel sandy with a few pea-sized lumps of butter still visible.

Toast the topping: Once the apples are done, transfer them to a bowl and keep warm. Wipe the skillet clean with a paper towel, then return it to medium heat. Add the oat mixture and stir constantly for 3 to 4 minutes. You’ll hear it crackle and pop as the butter melts—stop when the oats turn golden brown and smell nutty and toasty.

Assemble the bowls: Divide the warm apple mixture among four bowls. Spoon the toasted oat topping over each portion, letting it tumble unevenly over the fruit. If you like, add a dollop of vanilla yogurt or a drizzle of double cream right in the centre—the cold cream against the warm apples is a lovely contrast.