Melt the 4 ounces unsweetened chocolate and 1/2 cup butter together in a small saucepan or in the microwave, stirring until smooth. Set aside.
On a paper plate, whisk together flour and salt; set aside.
In a mixing bowl with electric beater, beat the eggs until fluffy, about 1 minute. Gradually beat in brown sugar. Add the cooled chocolate mixture and 2 teaspoons vanilla. Stir in flour mixture until blended. Blend in walnuts and 1/2 cup mini semisweet chocolate chips.
Spread the batter in a buttered 13x9-inch baking pan. Bake at 325 degrees for 20–22 minutes or until toothpick inserted in center comes out clean. Cool in pan on wire rack.
Cream remaining 1/2 cup butter and all the cream cheese together in a bowl until light and fluffy. Gradually beat in 1 teaspoon vanilla and powdered sugar; mix in dried cranberries.
Spread mixture over cooled brownies. Refrigerate until set.
Melt 1/4 cup semisweet chocolate chips and cream over low heat or in the microwave. Cool slightly. Dip a fork into the mixture and drizzle over the cranberry layer.