Heat 1 Tablespoon extra virgin olive oil in a large skillet over medium-high heat. Pat shrimp dry with paper towels then season on both sides with garlic salt and pepper. Add to skillet then saute until pink on both sides and just barely cooked through, 1-2 minutes per side. Remove to a plate then set aside.
Heat remaining Tablespoon extra virgin olive oil and 1 Tablespoon butter in skillet then add mushrooms and shallots. Saute until mushrooms are golden brown, 7-8 minutes then add zucchini and garlic, season with salt and pepper, and saute until zucchini are just starting to become tender. Add chicken broth then turn heat up to high and boil until broth has reduced by 1/2.
Meanwhile, bring a large pot of salted water to a boil then add spaghetti and cook until just barely al dente - spaghetti will cook a bit more in the sauce. Drain then set aside.
Once broth has reduced, remove skillet from heat then add pasta, parmesan cheese, basil, lemon juice, and remaining 1 Tablespoon butter and then toss until combined. Add shrimp then toss to heat through and serve.