Thaw frozen shrimp in cool water for about 15 minutes, peel and devein them, then pat dry.

Heat broth in a saucepan over medium-high until simmering, then lower the heat to keep it warm.

Melt 2 tablespoons of butter in a skillet, add onion or shallot, and sauté for 5-7 minutes until soft.

Stir in Arborio rice, coat with butter, and toast for 2-3 minutes until slightly translucent.

Add the dry white wine, stirring until mostly absorbed, about 1-2 minutes.

Add warm broth one ladle at a time, stirring frequently, until the rice is creamy and al dente, about 25-30 minutes.

Remove from heat and mix in the remaining butter, lemon juice, lemon zest, and Parmesan cheese.

In a separate skillet, melt remaining butter and sauté shrimp with garlic and red pepper flakes for 2 minutes per side until pink.

Plate the risotto, top with sautéed shrimp, and garnish with fresh parsley and extra lemon juice.