Preheat the oven to 220°C / 430°F. A hot oven (about 220°C) gives sweet potatoes quick surface caramelization and crisp edges while keeping the interiors tender. Line a rimmed baking sheet with parchment or a thin film of oil to prevent sticking.

Toss the cubed sweet potatoes with 1 tbsp olive oil, 1 tsp smoked paprika, 1/2 tsp ground cumin, 1/2 tsp kosher salt and 1/4 tsp black pepper. Distribute in a single layer on the baking sheet, leaving space between cubes. Coating with oil and spice helps the surface brown and the paprika bloom (release its aroma) when roasting; spacing prevents steaming and promotes crispness.

Roast the sweet potatoes for 20–25 minutes, flipping once halfway through. Roast until edges are deeply golden and a paring knife meets little resistance — the flip encourages even browning. If using a convection oven, check at 18 minutes.

While sweet potatoes roast, prepare the chickpeas: pat the drained chickpeas mostly dry on a towel (moisture prevents crisping), then toss with 1 tbsp olive oil, remaining 1 tsp smoked paprika, 1/2 tsp ground cumin, crushed red pepper flakes, and a pinch of salt. Spicing the chickpeas twice (with sweet potatoes and again here) layers the smoky flavor throughout the dish.

Heat a large nonstick or heavy skillet over medium-high heat until shimmering. Spread spiced chickpeas into the pan in a single layer and let them cook undisturbed for 3–4 minutes to develop a crust; then shake or stir every 2 minutes until most chickpeas show darkened, toasted patches (another 4–6 minutes). High, dry heat crisps the chickpeas and deepens their nuttiness—avoid overcrowding the pan or they'll steam instead of crisp.

When chickpeas are browned and crisped, remove them to a plate and reserve the pan. If the pan is dry, add a drizzle of oil before the next step; you want a fond (browned bits) to build flavor in the hash.

In the same large skillet, add the butter and remaining 1 tbsp olive oil over medium heat. Add the diced onion and a pinch of salt and cook, stirring occasionally, until translucent and starting to brown at the edges (6–8 minutes). Browning the onion develops sweetness and an aromatic base for the hash.

Add the minced garlic and the remaining 1/2 tsp cumin; cook 30–45 seconds until fragrant. Toasting the cumin briefly in the fat blooms its essential oils—don’t let the garlic burn, which makes it bitter.

Add the roasted sweet potatoes to the skillet with the onions and fold gently to combine. Cook 2–3 minutes to allow the flavors to marry and to pick up any browned bits from the pan. If the sweet potatoes are very soft, toss gently to avoid turning them to mush—you're aiming for contrast between crisped bits and tender interior.

Return the crispy chickpeas to the pan and stir to distribute. Taste and adjust seasoning with more salt and pepper if needed. Reintroducing the chickpeas at the end keeps them crunchy.

While the hash finishes, heat a separate medium skillet over medium heat and add a tablespoon of olive oil. Add the chopped kale, a pinch of salt and 1 tablespoon lemon juice, then sauté briskly for 3–4 minutes until the kale is wilted but still bright green. Sautéing kale quickly in hot oil and lemon preserves color and texture while the acid brightens the bitter greens.

Toss the lemony kale into the sweet potato and chickpea hash (or serve to the side). Finish the dish with the remaining tablespoon of lemon juice and chopped parsley; add crumbled feta or a dollop of Greek yogurt if using. The fresh lemon and parsley lift the smoky, earthy flavors and add contrast to the richer roasted notes.

Plate the hash in shallow bowls or on warmed plates. Optionally garnish with extra smoked paprika, flaky sea salt, and more parsley. Serve immediately so the chickpeas retain their crisp texture.