"Create a French industrial-style brownie recipe optimized for the longest possible shelf life at room temperature, using pasteurized egg yolks. Be honest that true 3-month ambient shelf life is difficult and usually requires validation; nevertheless, formulate for maximum ambient stability with low water activity, sealed high-barrier packaging, and optional legally permitted preservatives. Use imperial-style units? No, use metric/industrial units in kilograms because the user requested kg. Include approximate shelf-life ranges for ambient, refrigerated, and frozen storage, and note that ambient 3 months is not guaranteed. Keep it practical and food-safe. Emphasize dark chocolate brownie texture and industrial production."