Slice 1 small onion into 8 to 9 thin rings, if using a whole onion.

Combine the 8 to 9 onion rings with 1/2 tsp black pepper and 1 tsp chilly powder in a mixing bowl.

Add salt to taste and 1/2 tsp lemon juice, then toss the onion mixture until evenly coated.

Spread 1 tbsp green chutney evenly over one side of each bread slice.

Divide the seasoned onion rings over the chutney-coated bread slices.

Place 1 cheese slice on top of the onions on each bread slice.

Toast the open-faced cheese toasts in a preheated sandwich grill until the cheese melts and the bread edges are crisp, about 4 to 5 minutes.

Remove the hot cheese toast carefully and serve immediately while crisp and melty.