Easy Hot Fudge Pie

Ingredients

½ cup unsalted butter, melted

1 cup granulated sugar

¼ cup unsweetened cocoa powder

2 eggs

1 tsp vanilla extract

¼ cup all-purpose flour

¼ tsp salt

½ cup semi-sweet chocolate chips (optional, for extra fudginess)

Whipped cream or vanilla ice cream (for serving)