- In a large mixing bowl, combine warm milk, warm water, vegetable oil, granulated sugar, and dry yeast. Let it sit for 5-10 minutes until the yeast is activated and bubbly.

- Add flour and salt to the mixture gradually, mixing with a spoon or hand until a dough forms.

- Knead the dough on a floured surface for about 10 minutes until it becomes smooth and elastic.

- Place the dough in a lightly greased bowl, cover with a damp cloth, and let it rise in a warm place for about 1 hour or until it doubles in size.

- In a bowl, combine grated cheese, chopped red, green, and yellow bell peppers, onions, green onions, and tomatoes (if using). Season with salt and pepper to taste.

- Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.

- Punch down the risen dough and roll it out on a lightly floured surface into a large rectangle (about 1/4 inch thick).

- Evenly spread the filling mixture over the rolled-out dough.

- Starting from one end, carefully roll the dough into a tight log, similar to how you would roll cinnamon rolls.

- Slice the log into 1-inch thick pieces and place them cut-side down on the prepared baking sheet.

- Bake in the preheated oven for 20-25 minutes or until the pinwheels are golden brown and the cheese is melted and bubbly.

- Remove from the oven and let them cool slightly on a wire rack before serving.