Montmorency Tart Cherry Streusel Coffee Cake

Ingredients

• 1 1/2 cup old fashioned oats
• 1 cup unbleached all-purpose flour
• 1 cup light brown sugar
• 2 teaspoons ground cinnamon
• 1/4 teaspoon kosher salt
• 1 stick unsalted butter (1/2 cup) cold, cut into small pieces
• 1 1/2 cups frozen Montmorency tart cherries, thawed and drained
• 2 1/4 cups unbleached all-purpose flour
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1 1/4 cup granulated sugar
• 2 sticks (1 cup) unsalted butter, softened
• 2 large eggs
• 1 teaspoon vanilla extract
• 8 ounces sour cream
• 1 cup powdered sugar
• 1-2 Tablespoons Montmorency tart cherry Juice