Maple Apple Muffins

Ingredients

• 8 tablespoons(1 stick) butter
• 1 cup light brown sugar
• 2 large eggs
• 1 cup all purpose flour
• 1 cup whole wheat flour
• 1 teaspoon baking soda
• 1 teaspoon cinnamon
• 1/2 teaspoon salt
• 1/2 cup Greek yogurt (vanilla or plain)
• 1 teaspoon vanilla extract
• 1/2 cup pure maple syrup
• 2 cups chopped apples
• 1/2 cup light brown sugar
• 1/4 cup flour
• 1/4 cup quick oats
• 1/2 teaspoon cinnamon
• 4 tablespoons butter (or maple butter)