In a medium saucepan, pour in the chicken broth and heat it over medium heat. Bring the broth to a gentle simmer, then reduce the heat to low, keeping it warm throughout the cooking process.

In a Dutch oven, melt 3 tablespoons of unsalted butter over medium heat. Add the chopped leek and assorted mushrooms, seasoning with kosher salt and freshly ground black pepper. Sauté the mixture until the mushrooms turn golden brown and tender, about 8 to 10 minutes. Add the minced garlic, cooking for an additional minute until fragrant.

Stir in the Arborio rice, ensuring it becomes well-coated in the buttery mixture. Continue to cook, stirring frequently for about 3 minutes until slightly translucent and nutty. Pour in the dry white wine, allowing it to cook down completely until absorbed.

Gradually ladle in the warm chicken broth, one cup at a time, stirring continuously. Wait until the broth is mostly absorbed before adding more, which should take about 20 to 25 minutes in total.

In a separate skillet, melt the remaining butter and sauté the sliced radishes until they are golden brown and tender. Once the risotto has thickened adequately, stir in the Parmesan cheese, heavy cream, lemon zest, lemon juice, peas, spinach, fresh thyme leaves, and the sautéed radishes until well combined.

Garnish the risotto with the remaining chopped chives and a sprinkle of lemon zest. Serve warm and enjoy.