Mo Cheese Mo Better Cheesy Potatoes

My daughter asked me to make "cheesy" potatoes for a retirement party. I checked out a number of recipes and then created one of my own. My daughter was concerned they would be too cheesy, but one of the guests said, "mo cheese, mo better" and thus came the name. She loved them. I had nothing to bring home after the party. Thought I should document this recipe for future use as I have a feeling I will be asked to make this again.

• Ready In: 1 hr 20 mins
• Serves: 24-30

Ingredients

• 4 (28 ounce) bags  o'brien frozen potatoes (chopped type)
• 1  quart half-and-half
• 1  cup margarine
• 32  ounces Velveeta cheese (cubed)
• 16  ounces  shredded cheddar cheese
•  salt and pepper
• 2  onions (chopped)

Directions

1. Pour O'brien potatoes in large food pan (20 3/4" x 12 3/4" x 2 1/2" Deep). Set aside.
2. In a large sauce pan combine next 4 ingredients and heat over medium to low heat until smooth stirring often to be sure it doesn't burn.
3. Stir in chopped onions and pour over potatoes.
4. Bake uncovered at 350 degrees for one hour or until bubbly and browned on top (may take a little longer than one hour). (I'm a temperature taker and made sure they were 160 degrees or more.)
5. Allow to rest before serving. (I let them set for an hour and then put them in a 250 degree oven to be sure they were warm for serving.).