Wash the cranberries and spread on paper towels to dry. Spray a 9-inch springform pan with cooking spray, and line the bottom with a circle of parchment or aluminum foil. Preheat your oven to 350 degrees. Wash and zest 2 oranges.
Crumb Topping:
In a small bowl, combine the flour, brown sugar, salt, zest, and softened butter. Mix with your fingers (or a fork) until crumbly. Stir in the sliced almonds; set aside.
Batter:
Pat the cranberries dry and cut them in half; set aside.
In a large bowl, combine the flour, sugar, salt, baking powder, soda, and soft butter. Beat on low speed with an electric mixer for 1-2 minutes, or until the mixture reaches a sand-like consistency.
Beat in the eggs and vanilla, then the buttermilk. Beat for another minute or until the mixture is smooth, occasionally scraping the sides of the bowl with a rubber spatula. Fold in the cranberries and orange zest.
Spread the batter into the prepared pan. Sprinkle the crumbs evenly over the top of the cake.
Bake in a preheated oven at 350° for 30 minutes. Turn the heat down to 325° and bake for another 35-40 minutes, or until a toothpick inserted in the middle comes out clean or with moist crumbs but no wet batter.
Let cool in the pan for about 10 minutes, then run a metal spatula or knife around the sides of the pan. Remove the sides of the pan, and carefully remove the parchment from the bottom of the cake.
Serve warm or at room temperature.
Notes
Do not use a 9" cake pan; it will overflow. If you don't have a springform pan, you can use a 9-inch square pan instead.
Frozen cranberries will also work, you just need to increase the baking time by a few minutes because they make the batter cold.
Instead of using orange zest, you can use 1/2 teaspoon of almond extract in the batter and 1/8 teaspoon of almond extract in the topping.
If you don't have buttermilk, you can use Greek yogurt, sour cream, or plain yogurt.
Leftover coffee cake can be stored at room temperature for 4-5 days. I like to wrap it in plastic wrap and place it in an airtight container.