Preheat oven to 350 degrees.
Heat a skillet over medium high heat & add oil, onions & red peppers. Saute for few minutes.
Add the diced potatoes,cover and reduce heat to medium allowing the potatoes to brown. Stir occasionally for about 8-10 minutes.
Season with salt and pepper.
In a small bowl, combine milk and flour with a whisk. Add to the potatoes and cook just until it thickens (stir constantly). This should take only 2-3 minutes.
Remove from heat and add the vegan sour cream and vegan cheese.
Spoon into a prepared baking pan.
In a small bowl, combine the topping ingredients and spread over the potato mixture.
Bake for about 20-30 minutes or until bubbly and golden.