In a large sauté pan on medium heat melt butter.
Add onion, pepper, zucchini, jalapeño and broccolini. Cook until onion has softened and begins to caramelize and broccolini is tender. Add roma tomato, lemon juice and lemon zest. Cook an additional minute.
Add pasta and toss to coat. Season with salt and pepper to taste and garnish with thinly sliced lemon.