Preheat your oven to 350 Degrees Fahrenheit.
In a large non-sticking saucepan, mix up yellow squash cubes and chopped onion. Sprinkle freshly ground pepper and salt over the squash-onion mixture and pour in some water.
Now place the lid of the saucepan at the top to cover it and bring the mixture to a boil on the stove, with a medium heat level. Keep an eye on the cooking mixture, use a wooden ladle to stir it occasionally and add in more water- if required. Continue cooking until the ingredients are lightly tender.
Remove the saucepan from the stove and use a large colander to drain the squash and onions.
Return the drained squash-onion mixture to the saucepan and set, add in four tablespoons of butter. Sprinkle some more salt and pepper along with seasonings and adjust it according to your taste.
Stir in saltine crumbled crackers and continue mixing until it turned into a buttered casserole.
Drizzle the milk over the buttered casserole and mix well.
Grab a large non-sticking baking dish and butter one and half of its quart. Pour the buttered casserole into this baking dish and level its surface with the backside of a wooden ladle.
Scatter some shredded Cheddar cheese over the surface and top with finely chopped pecans.
Place the baking dish in the preheat oven and bake it at the same temperature for the next 20 to 15 minutes or until the milk is absorbed and it forms a nicely browned bubbly Squash Casserole.
Remove your Mouth Watering Squash Casserole from oven and serve warm. Enjoy!