It’s basically a bechamel sauce with cheese and spices
1 tbsp butter
1 tbsp flour (any kind)
1 cup warm milk
1 cup shredded cheese, I used spicy jack
1 tsp mustard powder
1/2 tsp chili powder
Salt, pepper
Heat the butter until melted, add the flour and cook it for about 5 mins until golden brown and raw smell of flour is gone, add the milk slowly stirring constantly to remove any lumps. Keep it on the heat, stir constantly. Once it starts to thicken, add the cheese and spices,keep stirring all the time and allow to thicken.
After the sauce has cooled down a little, toast the bread, spread the sauce on the toast and put it under the broiler for just a few mins until the cheese starts to brown.