For the sauce: In a small pot, add the chicken stock, and bring to a boil. Reduce the heat and simmer until the liquid is reduced to ¼ cup. Add the cardamom, gradually whisk in the butter, and remove from the heat. Incorporate the lemon juice and sherry and strain into a small saucepan. Season; add the zucchini and squash and set aside, keeping warm.
For the Salmon
Brush salmon steaks with oil. Sprinkle with salt and pepper.
Place salmon in/on the oven/grill.
Cook salmon until opaque in center.
To serve, spoon some of the sauce onto a plate, place vegetables on the plate; place a fillet on top of vegetables.