Measure everything and bring the stock to a gentle simmer in a small saucepan. If using saffron, crush the threads lightly between your fingers and steep them in 1–2 tablespoons of the warm stock for 3–5 minutes to bloom the flavor and color. (Blooming saffron unlocks its aroma and gives a deeper golden color to the rice; if using turmeric, stir it into the stock directly.)

Pat the shrimp dry with paper towels and season both sides lightly with salt, pepper and a pinch of smoked paprika. Dry shrimp sear better; seasoning early allows flavors to penetrate the flesh.

Heat a 10–12 inch heavy skillet (preferably stainless steel or cast-iron) over medium-high heat and add the olive oil. When the oil shimmers but isn’t smoking, add the shrimp in a single layer and sear 30–45 seconds per side until just opaque with a thin golden edge. Remove the shrimp to a plate — do not overcook now because they will finish cooking later. Searing creates Maillard flavor that gives the shrimp a savory crust.

Lower the heat to medium and add the chopped onion to the skillet. Sauté 3–4 minutes until translucent and just beginning to color; this builds a sweet savory base. Add the minced garlic and toast for 20–30 seconds until fragrant — garlic burns quickly, so keep it moving.

Stir in the smoked paprika and the bloomed saffron (with its soaking liquid) or the turmeric, and cook for 20 seconds. Toasting the paprika releases its smoky oils and deepens the color; the saffron or turmeric needs only a brief heat to perfume the stock.

Pour in the warm stock and scrape the pan to deglaze — loosen the browned bits stuck to the bottom. Bring to a gentle simmer, taste and adjust salt and pepper. The simmering liquid will concentrate flavor and is what the rice will soak up.

Stir in the cooked rice and the frozen peas. Spread the mixture into an even, shallow layer in the pan. Press lightly with the back of a spoon so the rice makes contact with the pan surface — this encourages some grains to crisp and pick up extra texture (the classic paella crust or socarrat effect, achieved quickly here). Simmer uncovered for 3–4 minutes until the rice is heated through and the peas are tender.

Nestle the seared shrimp back into the rice so they sit on top; cover the skillet with a lid or foil for 1–2 minutes to finish cooking the shrimp through with gentle steam. Carryover heat will cook them to tender perfection without becoming rubbery.

Remove the lid, squeeze the lemon wedge over the rice, and adjust seasoning with a final pinch of salt or extra smoked paprika if desired. Serve immediately so shrimp stay juicy and the rice keeps a bit of bite.

Optional plating suggestion: spoon the rice into a shallow bowl, arrange the shrimp on top, scatter a small drizzle of olive oil and a few lemon zest threads for brightness. The contrast of saffron-golden rice, green peas and pink shrimp is visually appealing and appetizing.