Finely chop the radishes—you want small pieces for even distribution and a pleasant texture (a quick pulse in a food processor works too, just avoid over-processing).

In a bowl, combine the softened butter, chopped radishes, lemon zest, herbs, and flaky salt. Mix until well combined.

Add a bit more salt or lemon zest if needed. A crack of black pepper is optional but nice.

Spread generously over warm grilled or toasted bread. Finish with an extra sprinkle of flaky salt if desired.