Heat the chicken or vegetable broth in a medium saucepan and keep it warm over low heat throughout the cooking process.

In a large, heavy-bottomed pan or Dutch oven, heat 2 tablespoons of butter and the olive oil over medium heat. Add the diced onion and cook for 4-5 minutes until softened and translucent. Add the minced garlic and cook for another minute until fragrant.

Add the Arborio rice to the pan and stir constantly for 2-3 minutes until the grains are well-coated and slightly translucent around the edges. Pour in the white wine and stir until it's almost completely absorbed.

Begin adding the warm broth one ladle at a time, stirring frequently. Wait until each addition is almost completely absorbed before adding the next ladle. Continue this process for about 18-20 minutes until the rice is creamy and tender but still has a slight bite.

When the rice is almost done, stir in the peas and cook for 3-4 minutes until they're tender and bright green. If using frozen peas, they'll need just 2-3 minutes to heat through.

Remove the pan from heat and stir in the remaining tablespoon of butter and the grated Parmesan cheese. Stir vigorously until the risotto is creamy and well combined. Season with salt and pepper to taste.

Serve immediately in warm bowls, garnished with additional Parmesan cheese and fresh herbs if desired. The risotto should be creamy and flow slightly when plated.