1. 1. Prepare the Potatoes: Start by boiling the quartered new potatoes in a large pot of salted water until they are tender, about 10-12 minutes. Drain them well and set aside. They should be easily pierced with a fork but not falling apart.

2. 2. Saute the Onions and Garlic: While the potatoes are cooking, heat the olive oil in a large skillet or Dutch oven over medium heat. Add the thinly sliced yellow onions and cook, stirring occasionally, until they are softened and translucent, about 8-10 minutes. Stir in the minced garlic, dried thyme, black pepper, and salt, and cook for another minute until fragrant.

3. 3. Build the Creamy Sauce: Pour in the vegetable broth and bring it to a simmer, scraping up any browned bits from the bottom of the pan. Stir in the heavy cream. Once simmering, slowly whisk in the cornstarch slurry. Continue to cook, stirring constantly, until the sauce thickens to your desired consistency, about 2-3 minutes. It should be thick enough to coat the back of a spoon.

4. 4. Combine the Boil Ingredients: Add the cooked potatoes and sliced smoked sausage to the creamy garlic onion sauce. Stir gently to ensure everything is well coated and heated through. Let it simmer for 5 minutes to allow the flavors to meld. The sausage should be warmed and the potatoes thoroughly coated.

5. 5. Prepare the Whipped Feta: While the boil is simmering, combine the crumbled feta cheese, plain Greek yogurt, and fresh lemon juice in a small food processor or blender. Process until smooth and creamy, scraping down the sides as needed. The mixture should be light and spreadable.

6. 6. Serve and Garnish: Ladle the creamy garlic onion boil into bowls. Dollop a generous spoonful of the whipped feta on top of each serving. Garnish with fresh chopped parsley for a burst of color and freshness. Serve immediately.