Italian Grape Cake – Easy Rustic Dessert with Olive Oil

Ingredients

• 1½ cups all-purpose flour, (spooned into measuring cup and leveled-off)
• ½ teaspoon salt
• 1 teaspoon baking powder
• 2 large eggs
• ⅔ cup + 1 tablespoon sugar, (divided)
• 1/3 cup milk ((low fat is fine))
• ¼ cup olive oil
• 4 tablespoons unsalted butter, (melted, plus more for greasing the pan)
• 2 teaspoons lemon zest, (from one lemon)
• 1 teaspoon orange zest, (from one orange)
• 1 teaspoon vanilla extract
• 2 cups seedless red grapes, (divided)