Prepare all ingredients as instructed above.
Make the Meat Sauce: Heat a pot over medium heat. Add olive oil, then sauté the sliced garlic and diced onion until softened.
Add the ground beef and cook until browned, breaking it into small pieces with a spatula.
Stir in the crushed tomatoes and season generously with salt and pepper. Partially cover with a lid and simmer on low for 30–35 minutes.
Cook the pasta: Bring a pot of water to a boil. Cook the pasta according to package instructions until al dente. Drain, reserving pasta water if desired.
Add the drained spaghetti to the pot with the meat sauce and mix well to coat.
Heat the oil in a non-stick pan over medium heat. Add peas and season with salt and pepper. Cook, stirring frequently, until peas are tender and heated through (about 3–5 minutes).
Make the Sparkling Water: Combine sparkling water and lemon.
Serve: Serve the spaghetti with grated Parmesan cheese, alongside sautéed peas and lemon sparkling water.