Preheat the oven to 350 degrees Fahrenheit.

In a large bowl, combine the grated Cheddar and Jack cheeses.

Add the mayonnaise, cream cheese, mashed pimentos, house seasoning, grated onion, and cracked pepper.

Using an electric mixer, beat all ingredients together until well combined and smooth.

Spread the pimento cheese mixture evenly on one side of each slice of white bread.

Roll each slice of bread up tightly, jelly-roll style.

Arrange the fresh tomato slices in an 8 x 11 x 2-inch baking dish, ensuring they cover the entire bottom of the dish.

Sprinkle half of the chopped fresh oregano (or dried oregano) and additional house seasoning over the sliced tomatoes.

Place the rolled-up bread slices on top of the sliced tomatoes.

Pour the canned diced tomatoes with green chilies evenly over the bread rolls.

Sprinkle the remaining oregano over the top of the dish.

Bake in the preheated oven for 30 minutes, or until the bread rolls are golden brown and the tomatoes are bubbly.