Bring the tenderloin to room temperature: remove the beef from the refrigerator and pat dry with paper towels. Season evenly with 2 tsp kosher salt, 1 tsp freshly ground black pepper, and 1 tsp smoked paprika. Drizzle with 2 tbsp olive oil, then rub in 2 minced garlic cloves, 1 tbsp fresh thyme leaves and 1 tbsp lemon juice. Let sit 20–25 minutes. WHY: Allowing the meat to warm shortens cooking time and yields more even doneness; the salt and oil help extract flavor and form a surface seasoning that will brown beautifully on the grill or pan.

Prepare the squash–zucchini ribbons: using a vegetable peeler, shave the zucchini and yellow squash into long ribbons and place in a large bowl. Toss with 1 tbsp olive oil and 1/2 tsp kosher salt. WHY: Peeling into ribbons creates delicate, silky strands that cook quickly and provide a tender-crisp texture; tossing with oil and salt seasons them evenly and prevents sticking when cooking.

Start the rice: heat a medium saucepan over medium heat, add 2 tbsp butter. When it foams, add 1 medium finely diced onion and 1 minced garlic clove. Sauté until translucent and fragrant, about 3–4 minutes. WHY: Gently sweating the onion and garlic in butter builds a savory base — the fat carries flavor into the rice.

Toast the rice: add 1 1/2 cups (≈270 g) uncooked long-grain white rice to the saucepan and stir for 1–2 minutes to coat each grain in butter and lightly toast. WHY: Toasting rice for a minute or two blooms a nutty aroma and helps the grains stay separate when cooked.

Add liquid and tomatoes: pour in 3 cups (720 ml) low-sodium chicken stock and 2 diced medium tomatoes. Bring to a gentle boil, cover, reduce heat to low, and simmer 15–18 minutes until the liquid is absorbed and rice is tender. WHY: Cooking covered traps steam to cook rice evenly; adding tomatoes during the simmer infuses the rice with bright acidity and color.

Finish the cheesy tomato rice: remove the pan from heat, let sit covered 5 minutes. Stir in 1 cup (≈100 g) grated sharp cheddar and 1 tbsp butter; season to taste with salt and pepper and chopped parsley if using. WHY: Resting allows trapped steam to finish cooking the rice; stirring in cheese and butter off heat creates a glossy, creamy texture without overcooking the cheese.

Preheat your grill or cast-iron skillet to high (about 450–500°F / 230–260°C). Oil the grates or pan lightly. WHY: A very hot surface produces an immediate sear that locks in juices and develops deep, flavorful browning (Maillard reaction).

Grill or sear the tenderloin: place the seasoned tenderloin on the hot grill or skillet. Sear 2–3 minutes per side to develop a dark crust, then reduce heat (or move to indirect heat on the grill) and continue cooking until the internal temperature reaches 125°F (52°C) for medium-rare, about 10–15 minutes total depending on thickness. Use a meat thermometer for accuracy. WHY: Initial high-heat sear creates flavor; finishing at a gentler heat ensures the interior cooks to the target doneness without over-charring the exterior. Rest the meat 8–10 minutes tented in foil before slicing — carryover cooking will raise the temperature by a few degrees and resting redistributes juices.

Cook the ribbons: while the meat rests, heat a large nonstick skillet over medium-high, add the zucchini–squash ribbons in a loose pile and cook, tossing occasionally, for 2–3 minutes until just tender but still bright and slightly al dente. Finish with a pinch of salt, a squeeze of lemon if desired, and scatter chopped parsley. WHY: Quick cooking preserves a slight bite and fresh flavor; overcooking ribbons makes them watery and limp.

Optional eggs: if adding eggs, fry or soft-poach 4 eggs (one per plate) while the ribbons cook. A runny yolk adds richness and a silky sauce when cut over the steak and rice. WHY: Eggs balance the plate with an extra layer of unctuous texture and additional protein.

Slice and plate: slice the rested tenderloin into medallions 1/2–3/4" thick across the grain. Spoon a mound of cheesy tomato rice on each plate, tuck a nest of squash–zucchini ribbons beside it, and fan 3–4 slices of tenderloin over the rice. Top with a cooked egg if using and finish with a grind of black pepper and a drizzle of olive oil or a small pat of herb butter. WHY: Slicing across the grain maximizes tenderness and the arrangement keeps the rice warm while showing off the meat.