A while ago I had an orzo dish in a restaurant, where the Orzo had been cooked in the oven together with vegetable stock, garlic, herbs, and cherry tomatoes. The waiter said that the trick is to put the raw Orzo into the hot olive oil with garlic and top it up with the liquid to cook it directly in the oven. I tried to re-cook the dish but unfortunately, the orzo had either been too cooked/ sticky or not cooked through or got hard on the top. I tried to find similar recipes online but the orzo always seems to be precooked or cooked in tomato sauce. What would be the right liquid/orzo scale to cook orzo in the oven? 
I don't know about bacon literally melting in one's mouth.  I doubt that is possible.  However, the term "melts in your mouth," when referring to meat, is usually used to describe an ultra tender preparation. The sensation probably is mostly centered on how we perceive fat and collagen that were broken down during the cooking process.  Collagen and fat actually do melt, and proper cooking of proteins known to "melt in your mouth" keeps much of these melted elements within the final product. Alternately, when you eat a "dry" piece of meat, it is likely overcooked, and fat and collagen have drained from your final product. Fats and collagen melt at different temperatures, and depending on the preparation, need different cooking times to provide the ideal eating experience.  Often, these items are cooked "low and slow".  For example, say, a pork butt cooked at 190F (88C) for 12 to 18 hours, or a properly cooked stew.  Collagen melts as low as 160F (71C). Fats melt in the 130F to 140F (54C to 60C) range. No preparation of meat, that I am aware of, literally turns entirely to liquid in one's mouth. As an aside, this creates an issue for people who use sous vide/low temperature cooking, as sometimes cooking temperatures are below those needed to melt fats and collagen.  In that situation dramatically lengthening the cooking time can be helpful, if one wants to impact the texture of the final product. 