Place a large heavy duty pan, over medium heat, sauté onion in 2 Tablespoons olive oil (set aside other 1 Tablespoon) and butter for 3 minutes. Add rice and garlic, stirring for about 1-2 minutes until risotto starts to sound like beach glass. Stir in white wine and let reduce while continuing to stir. Stir in 1 cup of broth; continue cooking and stirring until liquid is absorbed. Gradually stir in remaining broth 1 cup at a time, cooking and stirring until liquid is absorbed before adding the next cup until risotto is ala dente –– or cook a bit longer if desired. Remove risotto from heat and stir in parmesan cheese. Set aside.
In a large saute pan add remaining olive oil and place over medium high heat. Next add in zucchini and tomatoes, give a gentle stir then let sit for 2-3 minutes. Let sides of the zucchini begin to get slightly golden and the tomatoes begin to split open a bit. Stir a couple of times and let sit for another 1-2 minutes. Next add in the olives, rosemary, salt and pepper and continue to cook for another 2-3 minutes. Until zucchini and tomatoes are tender and golden. Remove from heat stir in fresh basil. Top mixture onto risotto and serve.