Preheat oven to 350°F. Coat an 8-inch-square baking pan with cooking spray.
Stir 1 1/4 cups graham cracker crumbs, 4 tablespoons butter and half the lemon zest together in a medium bowl. Press the mixture firmly and evenly into the prepared pan. Bake until lightly browned around the edges, about 10 minutes. Let cool in the pan on a wire rack for at least 10 minutes.
Meanwhile, thoroughly whisk 8 ounces softened cream cheese, 1/3 cup sugar, 1/4 cup sour cream (or yogurt), 1 egg, 3 tablespoons lemon juice, 1 teaspoon vanilla, 1/8 teaspoon salt and the remaining lemon zest together in a medium bowl. (Alternatively, combine ingredients in a food processor and process until smooth; transfer to a medium bowl and set aside.)
Add 1 cup cranberries and the remaining 2 tablespoons sugar to a food processor. Pulse until well chopped. Add to the cream cheese mixture and stir until incorporated. Pour the filling evenly over the baked crust. Bake until the center appears to be just set, 35 to 40 minutes. Cool to room temperature, then cover and refrigerate until cold, about 4 hours more.