Spiced Gingerbread Pear Upside-Down Cake

Ingredients

• 1/2 cup butter, melted
• 1/2 cup coarsely chopped walnuts
• 1/4 cup packed brown sugar
• 2 large pears, peeled and sliced
• 1/2 cup butter, softened
• 1/3 cup sugar
• 1 large egg, room temperature
• 1/3 cup molasses
• 1-1/2 cups all-purpose flour
• 3/4 teaspoon ground ginger
• 3/4 teaspoon ground cinnamon
• 1/2 teaspoon salt
• 1/2 teaspoon baking powder
• 1/4 teaspoon baking soda
• 1/2 cup warm water
• Ice cream, optional