Stage 1: Prepare the Filling

1. Grease the Slow Cooker: Liberally grease the inside of your slow cooker crock with butter or non-stick cooking spray. This is a crucial step to prevent the sugary filling from sticking and makes cleanup much easier.

2. Mix the Dry Ingredients: In a large mixing bowl, whisk together the ½ cup of granulated sugar and 6 tablespoons of all-purpose flour. Mixing the dry ingredients first helps prevent the flour from clumping when you add the wet ingredients.

3. Combine the Filling: Add the two cans of very well-drained crushed pineapple and the 1 ½ cups of freshly shredded sharp cheddar cheese to the bowl with the sugar and flour mixture. Stir everything together until it is just combined. Be careful not to overmix. The mixture will be thick.

4. Transfer to Slow Cooker: Scrape the pineapple and cheese mixture into your prepared slow cooker crock and spread it into an even layer.

Stage 2: Prepare the Topping

1. Crush the Crackers: Place the Ritz crackers in a large zip-top bag. Seal the bag, removing most of the air, and use a rolling pin or the bottom of a glass to crush them into coarse crumbs. You want a mix of fine crumbs and some larger, pea-sized pieces for the best texture.

2. Combine Topping Ingredients: In a separate small bowl, pour the ½ cup of melted butter over the crushed Ritz crackers. Use a fork to toss them together until all the crumbs are evenly coated in butter.

3. Add the Topping: Sprinkle the buttery cracker crumb mixture evenly over the top of the pineapple filling in the slow cooker.

Stage 3: Cook the Casserole

1. The Paper Towel Trick: Lay a clean paper towel or a folded tea towel over the top of the slow cooker crock before placing the lid on. This trick is essential for slow cooker “baking.” The towel will absorb the condensation that forms on the lid, preventing it from dripping down and making your cracker topping soggy.

2. Cook: Place the lid securely over the paper towel. Cook the casserole on the LOW setting for 2 ½ to 3 hours. The filling should be hot and bubbly around the edges, and the topping should be lightly golden.

3. Rest and Serve: Turn off the slow cooker and let the casserole rest with the lid off for about 10-15 minutes. This allows it to set up slightly before serving. Serve warm.