Preheat oven to 350 degrees. Bake cake as directed on the package for 13x9 inch pan. Cool 15 minutes. Poke top of warm cake every ½ inch with the handle of a wooden spoon. Wipe handle occasionally to reduce sticking. Drizzle sweetened condensed milk evenly over top of cake; let stand until milk has been absorbed into cake. Drizzle with desired topping. Cover and refrigerate about 2 hours or until chilled. Spread whipped topping over the top of the cake. Sprinkle with toffee chips. Cover and refrigerate until ready to serve Refrigerate the remaining cake after serving