Step 1

Adjust oven rack to middle position and heat oven to 400 degrees. Line large plate with paper towels. Grease 8-inch square baking dish. Cut Camembert in half horizontally to create 2 pieces of equal thickness. Cut each half into ¾-inch pieces.

Step 2

Place steamer basket in large saucepan. Add water to barely reach bottom of steamer and bring to boil over high heat. Add potatoes, cover, and reduce heat to medium (small wisps of steam should escape from beneath lid). Cook until potatoes are just cooked through and tip of paring knife inserted into potatoes meets little resistance, 15 to 17 minutes. Leaving potatoes in steamer, remove steamer from saucepan; set aside and let cool slightly, at least 10 minutes.

Step 3

While potatoes cool, cook bacon in 12-inch skillet over medium heat, stirring occasionally, until browned and chewy-crisp, 4 to 6 minutes. Using slotted spoon, transfer bacon to prepared plate; pour off all but 2 tablespoons bacon fat. Add onion and ½ teaspoon salt to fat left in skillet and cook over medium heat, stirring occasionally, until onion is softened and beginning to brown, about 7 minutes. Add thyme and garlic and continue to cook, stirring occasionally, until fragrant, about 2 minutes longer. Add wine and cook until reduced by half, about 2 minutes. Off heat, stir in cream, pepper, and remaining ¾ teaspoon salt.

Step 4

Add potatoes to skillet and stir gently to coat with onion mixture. Transfer half of potato mixture to prepared dish and spread into even layer. Top evenly with half of bacon. Add remaining potatoes and top evenly with remaining bacon. Arrange Camembert, rind side up, in even layer on top. Bake until bubbling and lightly browned, about 20 minutes. Let cool for 10 minutes before serving. Top each serving with spoonful of crème fraîche, if using.