Heat 1 tablespoon of the olive oil in a large high-sided skillet over medium-high heat. Add the onion, peas, carrots, asparagus, yellow squash, and zucchini. Season with salt and black pepper.

Cook, stirring frequently, until the vegetables are crisp-tender and lightly golden, about 4–5 minutes. Transfer the vegetables to a bowl and set aside.

Add the remaining olive oil and the Arborio rice to the skillet. Toast the rice for 1–2 minutes, stirring constantly.

Reduce heat to medium and pour in the white wine. Deglaze the skillet, gently scraping up any browned bits from the bottom. Cook until the wine is fully absorbed.

Add ½ cup of the warm broth to the skillet. Stir continuously until the liquid is absorbed, about 4–5 minutes. Continue adding broth ½ cup at a time, stirring constantly and allowing each addition to absorb before adding the next, until the rice is tender and creamy.

Stir in the reserved vegetables, Parmesan cheese, and lemon zest. Cook for 1–2 minutes, just until heated through.

Remove from heat and stir in the fresh parsley. Season with additional salt and black pepper, if needed. Serve immediately with extra Parmesan on the side.