Prep bread and asparagus: Cut bread into 1 inch cubes. Bring a small pot of water to a boil. Blanch asparagus for 2 minutes, drain, rinse with cold water, and pat dry.

Reduce salt in smoked salmon: Soak smoked salmon pieces in cold water for 20 minutes, changing the water once. Drain and pat dry.

Blend the custard: In a blender or food processor, combine eggs, milk, ricotta, flaxseed, mustard, lemon zest, onion powder, and pepper. Blend until completely smooth.

Cheese and herbs: In a bowl, toss 6 oz shredded Swiss with dill and chives. Reserve the remaining 2 oz Swiss for the topping.

First layer: Grease a 9x13 inch dish. Spread half of the bread in an even layer. Pour over half of the custard. Sprinkle with half of the Swiss herb mix. Scatter on half of the asparagus and half of both salmons.

Final layer: Repeat with remaining bread, custard, Swiss herb mix, asparagus, and salmons. Press down gently so the bread absorbs the custard. Mix the reserved 2 oz Swiss with the Parmesan and sprinkle evenly over the top. Dust with smoked paprika.

Chill and bake: Cover tightly and refrigerate for at least 4 hours or overnight. Heat the oven to 350°F (175°C). Bake covered for 40 minutes. Uncover and bake 15 to 20 minutes more, until puffed and golden and a knife inserted in the center comes out clean. Rest 10 to 15 minutes before slicing. The center should reach about 165°F (74°C).