Here is the lime Jello recipe. Make it the day before serving. I will look up the au gratin recipe for you later.

Buy the small box of lime flavored Jello and the small sized can of crushed pineapple and 8 ounces of sour cream. Drain the pineapple well, pressing the pineapple with a large spoon in a sieve to get the juice, and save the juice.

Follow the directions on the box for how much boiling and cold water to use to mix it, but use all the drained juice for the cold water, adding enough water to make it the right amount. Sometimes I use 2 or 3 tablespoons less of the cold water to help make the Jello firmer. When the Jello is thoroughly dissolved, stir in 1 cup of sour cream--I use a whisk and room temperature sour cream to make it combine well but do not beat it with the whisk or it will make it frothy, just stir it. Then cool it in the mixing bowl in the refrigerator until it is starting to set and is somewhat thickened. Stir in the crushed pineapple so it is evenly distributed and pour into a very lightly oiled mold or individual molds or custard cups. Put back in the refrigerator for several hours or overnight.

When it is time to serve, garnish the individual salad plate or serving plate with leaf lettuce. Run your finger around the edge of the mold to loosen the top of the mold from the very top of the edge. Fill a large bowl or the sink with hot water and dip the bottom of the mold up to the edge of the Jello into the hot water. 5 to 10 seconds for a custard cup size mold, 10 - 15 seconds for a large mold. Tip over the cup mold into your hand and give it a good shake. It should drop out onto your hand. For the big mold, quickly tip it onto the lettuce on the plate and give it a good shake to loosen it. Voila.

You can make a larger recipe by increasing all the ingredients if you are using a large mold. You could even make this in a lightly oiled glass baking pan, cut it into squares and use a spatula to lift out each serving.

Thank you Sheilajoyce!!

Katlan, I make Au Gratin this way.

White sauce on the stove.
Sliced taters on my mandolin, russet or new ..skins on

One layer of potatoes in buttered dish, sprinkle with salt, pepper, garlic and onion powder. Sprinkle grated cheese lightly. (Cheddar, medium or sharp usually.) another layer of potatoes..and just keep building layers till the pan is almost full about, 1/2" clearance to the top.
Pour white sauce over the whole thing..wiggle some of the potatoes to make it get in there. Cover and bake about an hour at 375-400. Pull off lid or foil and bake until a bit of brown is starting on the top. (You can bake at a lower temp if something else is in the oven..just might take 1.5-2 hours.)
This makes a 10" square pan for me. About 3 lbs of potatoes.
My white sauce is the medium thickness. 1/4 c butter, 1/4 c flour. 2-3 cups of liquid, some times I add almost a cup of chicken stock and the rest milk to the desired thickness.

I think I'm going to make the jello!

Thank you terri!!

I make au gratin potatoes in an easy way because I mix the cheese into the white sauce.

Butter the baking pan you will use. Peel and slice the potatoes thinly. My daughter likes to use unpeeled, washed potatoes, but I peel them. The peels do have a lot of nutrition.

Melt 1/4 cup butter and stir in 1/4 c flour. Cook over low heat 2 minutes to cook the flour. Stir in about 3-4 cups of whole milk, and simmer over low heat, stirring every now and then about 5 minutes till it is as thick as you like. You may have to add more milk as it thickens. Then stir in 1/2 pound or more of shredded cheddar cheese. Season with a dash of cayenne, pepper, salt and whatever else you might like such as onion powder or dry mustard or a dash of nutmeg or all of them.

I place two layers of sliced potatoes neatly across the bottom of the pan, then I season them with a shakes of salt and pepper and evenly spoon a layer of the cheese sauce over them. I end with a sauce layer on top. Repeat layering till the pan is full up to 1/2 inch from the top of the pan. Oil a sheet of foil and cover the pan. Bake in a 350 oven 1 hour, then remove foil to bake the last 15 minutes, and at this point you can sprinkle shredded cheddar cheese over the top for the last 15 minutes. They are done when the potatoes are tender when you pierce them with a sharp knife or a skewer. This dish holds well in a warm oven.