Preheat and prep: Heat the oven to 200°C / 400°F. Wash the potatoes and leave the skin on for texture and nutrition. Thinly slice the potatoes 2–3 mm thick (a mandoline makes this fast and even). Thin slices crisp faster and form the attractive top crust for the bake.

Par-cook the rice and pasta separately: Bring 1 cup rice to a simmer in 1 3/4 cups water with a pinch of salt, cover and cook 12 minutes off-high heat or until just tender (it will finish in the oven). In a separate pot, cook 1 cup short pasta in rapidly boiling salted water for 6–8 minutes until very al dente (pasta should still have a slight bite). Why: Partially cooking keeps both starches from over-softening during the longer bake and gives you distinct textures in the finished dish.

While grains cook, make the tomato–pepper ragout: Core and dice the tomatoes; seed and dice the peppers; finely dice the onion and grate or mince the garlic. Warm 2 tbsp olive oil in a sauté pan over medium heat, add the onion and a pinch of salt and sweat 4–5 minutes until translucent. Sweating (not browning) extracts sweetness from the onion without adding a bitter crust.

Add garlic and spices: Stir in garlic, 1 tsp oregano, 1 tsp thyme, and 1/2 tsp smoked paprika and cook 30–45 seconds to bloom the spices — heating spices in fat unlocks their essential oils and multiplies flavor. Add 1 tbsp tomato paste now if using and cook 1 minute to caramelize it slightly for depth.

Simmer the vegetables: Add the diced tomatoes and peppers, season with salt and pepper, and simmer gently 10–12 minutes until the mixture thickens to a sauce consistency. Taste and adjust seasoning — the ragout should be slightly brighter and more acidic than you want, because baking will mellow it.

Combine rice, pasta and ragout: Drain the pasta and fluff the rice with a fork. In a large bowl, combine the rice, pasta, and two-thirds of the ragout; fold gently to combine. Adding most of the ragout into the starch mix ensures the interior is saucy and well-seasoned while reserving some ragout for a glossy top layer.

Butter and oil the baking dish: Brush a 9 x 13-inch (or similarly sized) ovenproof dish with 1 tbsp olive oil and 1 tbsp melted butter. Why: A thin fat layer prevents sticking and helps the potato top brown and crisp.

Assemble the bake: Spread the rice-pasta-ragout mixture evenly into the dish. Spoon the remaining ragout across the top in an even layer for color and moisture. Arrange the potato slices in an overlapping circular or shingled pattern to cover the surface completely — this is your crust. As you place slices, tuck occasional thin carrot ribbons (use a peeler to shave) into the potato layer for sweetness and visual contrast.

Finish with butter and seasoning: Melt the remaining 3 tbsp butter with 1 tbsp olive oil and brush over the potato surface, then sprinkle a little salt and pepper. Butter encourages browning and gives the top a luxurious, crisp finish.

Bake: Place the dish on a rimmed baking sheet to catch drips and bake at 200°C / 400°F for 35–45 minutes until the potato top is golden and crisp at the edges and the interior bubbles. If the top browns too quickly, tent loosely with foil. Baking concentrates the ragout flavors and lets the starches absorb liquid, while the high oven helps the thin potato slices crisp rather than steam.

Rest and finish: Remove from oven and let rest 10 minutes to let juices settle — this makes slicing clean wedges easier. Sprinkle chopped parsley before serving for brightness.

To serve: Use a wide spatula to lift wedge-shaped pieces so each portion has a bit of crisp top and the saucy rice-pasta underneath. Serve with a green salad or simple yogurt-herb sauce if desired.