Preheat oven to 350 degrees Fahrenheit.

Cook red pepper, onion, zucchini, and Italian seasoning in butter or margarine in a large skillet over medium heat until tender.

Lightly grease an 8x8x2-inch baking pan.

Layer half of the saltine crackers in the bottom of the pan.

Spread half of the cooked vegetable mixture over the crackers.

Sprinkle half of the shredded cheddar cheese over the vegetables.

Repeat the layers: crackers, vegetable mixture, and cheese.

In a bowl, beat the eggs and milk together until well combined.

Pour the egg mixture evenly over the top cheese layer.

Bake in the preheated oven for 30-35 minutes, or until a knife inserted into the center comes out clean.

Let cool slightly before serving.