Place whole porcini mushrooms in a medium bowl. Cover with enough boiling water just to top mushrooms. Cover and set aside about 20 minutes or until mushrooms have reconstituted and are soft. Drain mushrooms (save porcini broth for risotto and transfer to a large deep saucepan). Chop mushrooms and set them aside.
To make risotto, warm chicken, or veggie broth in the same saucepan with the porcini broth; over low heat. Melt 3 tablespoons butter in a large saucepan or dutch oven, set over medium heat. Add the chopped shallot and cook for 3 minutes, stirring frequently. Add the garlic, thyme, porcini mushrooms, and salt + pepper, cook for 1 minute.
Stir in the Arborio rice and cook for 2 minutes. When the rice has taken on a pale, golden color, pour in wine, stirring constantly until the wine is fully absorbed.
Add ½ cup broth to the rice, and stir until the broth is absorbed. Continue adding broth ½ cup at a time (reserving ½ cup), stirring continuously, until the liquid is absorbed and the rice is al dente, about 15 to 20 minutes. Once cooked, stir in peas. Mix the lemon zest and Parmesan into the risotto and season to taste. The rice should flow and not be able to hold its shape and look very creamy, (add remaining hot stock to loosen rice, if necessary).
Season both sides of scallops with salt and pepper. Place on a paper towel-lined plate, dry well, and let sit for 15 minutes.
Heat large skillet over high heat. When hot, add oil. Carefully add the scallops and cook for 1 minute, undisturbed. Add butter to the pan, then flip the scallops and cook for an additional 1 to 2 minutes, depending on the size of the scallops.
Divide risotto into bowls. Top with scallops and brown butter. Garnish with more chopped parsley, and a little flaky salt on top (if using). Enjoy!