In a large saucepan, drizzle the olive oil over medium heat.
Once heated, add the garlic, bell pepper, and onion. Cook, stirring often, until beginning to soften and the garlic becomes fragrant.
Add the beef, breaking it up into small pieces. Season with the Xawaash spice mix, salt, and black pepper.
Cook, stirring occasionally and continuing to break the beef into pieces, until browned and cooked through.
Stir in the tomato paste, then add the diced tomatoes, sugar, and water.
Bring the mixture to a boil, then reduce heat to a simmer and cook, stirring occasionally, until thickened and the flavors are blended, about 30 minutes.
Season to taste with more Xawaash, salt, and/or black pepper.
Towards the end of simmering, bring a large pot of salted water to a boil.
Add the spaghetti and cook just until tender, al dente.
Drain the pasta and serve with the meat sauce along with fresh cilantro and bananas.