Sear the chicken thighs: Heat the olive oil in a large frying pan over medium-high heat until it shimmers. Add the chicken thighs in a single layer, without overcrowding. Cook for 3-4 minutes per side, until the underside turns a deep golden brown and releases easily from the pan. You'll hear a satisfying sizzle — that's what builds flavour. Transfer the browned chicken to a plate and set aside.

Sweat the vegetables: Reduce the heat to medium. Add the diced onion, carrot rounds, and celery slices to the same pan. Stir occasionally for 5-6 minutes, until the onion becomes translucent and the carrots soften slightly. The kitchen will smell sweet and savoury. Add the minced garlic and cook for 30 seconds more, just until fragrant.

Build the sauce base: Sprinkle the 2 tablespoons of plain flour over the vegetables and stir constantly for 1 minute. The mixture will look pasty and clumpy — that's exactly right. Slowly pour in about 250ml of the chicken stock while whisking, until the flour dissolves and the mixture thickens to a thin gravy consistency. This takes about 2 minutes of steady stirring.

Transfer to the slow cooker: Pour the vegetable mixture into the slow cooker. Add the remaining chicken stock, the whole milk, dried thyme, dried rosemary, salt, black pepper, and bay leaves. Stir well to combine. Nestle the browned chicken thighs into the liquid, making sure they're mostly submerged. The liquid should look pale golden and smell deeply herbal.

Slow cook the base: Cover and cook on high for 3 hours (or on low for 5-6 hours). After this time, the chicken should be fork-tender and shred easily. The sauce will have darkened slightly and thickened around the edges. Remove the chicken thighs to a cutting board and shred them with two forks. The meat should pull apart into long, juicy strands. Return the shredded chicken to the slow cooker and stir through. Remove and discard the bay leaves.

Make the dumpling dough: In a large mixing bowl, combine the self-raising flour with a pinch of salt. Add the cold butter cubes and rub them into the flour using your fingertips until the mixture resembles coarse breadcrumbs — you should still see small flecks of butter throughout. Pour in the 150ml of whole milk and stir with a wooden spoon until a soft, slightly sticky dough forms. Don't overmix, or the dumplings will be tough.

Drop in the dumplings: Lightly dust your hands with extra flour. Divide the dough into 12 equal portions and roll each into a rough ball — they don't need to be perfect spheres. Drop them gently onto the surface of the hot stew, spacing them evenly. They'll look like small, pale pillows floating on top. Cover the slow cooker immediately and cook on high for 30-45 minutes. Do not lift the lid during this time — the steam is what makes them light and fluffy.

Finish and serve: After 30 minutes, the dumplings should have puffed up and turned a pale golden colour on top. The exposed edges will look slightly dry and cracked, while the submerged bottoms will be tender. Garnish with fresh parsley if using, and serve immediately. The sauce should be thick enough to coat the back of a spoon, and the chicken will be falling apart in the most satisfying way.