Prepare ingredients: Prepare all ingredients as listed.
Cook aromatics: Heat a pot over medium heat. Add olive oil, then sauté sliced garlic and diced onion until softened.
Brown meat: Add ground beef and cook until browned, breaking into small pieces with a spatula.
Simmer sauce: Stir in crushed tomatoes and season generously with salt and pepper. Partially cover with a lid and simmer on low for 30–35 minutes.
Cook spaghetti: While the sauce simmers, cook spaghetti according to package instructions until al dente. Drain the pasta, reserving a bit of pasta water if desired.
Finish pasta: Add the drained spaghetti to the meat sauce and mix well to coat. Add pasta water to help the sauce meld with the pasta if desired. Stir in chopped basil.
Cook peas: In a sauté pan over medium heat, melt butter. Add green peas and sauté for 2–3 minutes until hot. Season with salt and pepper to taste.
Make lemon water: In a pitcher or large glass, combine sparkling water and lemon slices. Serve over ice, if desired.
Serve: Serve spaghetti topped with Parmesan cheese, alongside sautéed peas, sliced pears, and lemon sparkling water.