Ensure the two tablespoons of grass-fed butter are at room temperature so they spread easily later. Cut the half lemon into wedges and pluck some fresh dill sprigs in advance.
Toast the four slices of low-carb nut seed bread in a toaster or a dry skillet. Heat them until the edges lightly brown and the bread develops a crispy texture. Let the slices cool briefly on a rack after toasting, so the bottom doesn't become soft.
Spread the toasted bread slices with a generous layer of the softened butter. Break apart the 150 grams of smoked salmon and distribute the slices evenly over the buttered bread. Squeeze a lemon wedge over the fish and season everything with freshly ground black pepper.
Place the topped bread on a serving board or distribute it across plates. Lay the reserved fresh dill sprigs on the salmon and serve immediately.