Place potatoes into large saucepan and add enough water to cover, plus about 1 inch. Cook over medium-low heat until fork tender, about 15-20 minutes.In a medium saucepan, melt butter, add half and half. Heat until simmering.Drain potatoes and pour potatoes back into saucepan used to cook them. Mash potatoes over low heat until smooth. Add the melted butter and half and half mixture and boursin pieces to potatoes. Continue to mash the potatoes until creamy. Then, mix well with a wooden spoon until light, fluffy and smooth. Stir in salt and pepper.Pour potatoes into a serving bowl for serving.Make-Ahead Tip: Prepare mashed potatoes and pour into a casserole dish. Cover tightly with aluminum foil or a lid and refrigerate until about 20 minutes before ready to serve. Then, place in a preheated oven at 350º F for 20 minutes.When you remove from the oven, top with remaining 2 tablespoons of butter and a sprinkle of salt and pepper, if desired.Serve warm.