Melt butter and sweat shallots for about 5 min on medium heat. Add tomato paste and cook for 2 min. Add flour and cook for an additional 2 min. Pour in milk whisking constantly – bring to boil and cook for 2 min whisking swiftly. Season with nutmeg, salt and pepper. Turn oven on to 450ºF (230ºC) and start to beat egg whites with a pinch of salt and a few drops of lemon juice on medium speed. Remove sauce from the heat, add cheese and yolks; keep warm. In the mean time, in a food processor blend half of the salmon with some of the sauce. Transfer mixture and remaining sauce in a large bowl. Add lemon confit or zest and juice and remaining salmon. Set egg whites on full speed until fluffy but not grainy (Do not overwhip). Incorporate whipped egg whites in 2 batches. Fill up 8 greased ramekins or 7 round pastry rings (3.14’’x1.8’’/8x4.5cm) lined with greased parchment paper, or one large greased shallow dish.
Put in the oven and drop the temperature from 450ºF to 350ºF/180ºC and bake souffle for 25 minutes. Now you have 90 sec before it begins to deflate. Serve immédiately!