Melt the butter in a skillet over medium heat.
Once the butter is sizzling, add the onions to the skillet and saute for 1-2 minutes.
Add the peppers and saute for 3-4 minutes or until tender. Reduce the heat if the onions are cooking too quickly.
Add the garlic and saute for another 1-2 minutes or until fragrant.
Turn off the heat and set aside.
Preheat the oven to 350 F and grease a baking dish with butter.
Cook the pasta in boiling salted water until soft or al dente depending on your preference.
Drain and return the pasta to the hot pot and immediately move onto the next step.
In the same pot, add the prepared veggies, evaporated milk, mayonnaise, gouda, and parmesan cheese.
Season with salt and pepper to taste.
Mix until the cheese starts to melt then transfer the pasta to the baking dish.
Top with extra shredded Gouda and parmesan cheese.
Bake for 20-25 minutes or until the cheese has melted and the top is golden. You may also broil the dish for 2-3 minutes for a crispy golden-brown top.
Remove from the oven and allow to sit for 10 minutes before serving. Enjoy!