Place the flour, lemon rind, honey, 160g of the butter, and the egg in a large bowl. Work into a crumbly dough; knead into a smooth dough with floured hands. Shape into a ball and wrap in cling film; chill for 30 minutes.
Preheat the oven to 180 degrees C. Line 2 large baking trays with baking paper.
For the topping, lightly toast the sunflower seeds with the honey, the remaining butter and the cream in a saucepan. Remove from heat and allow seeds to cool.
Roll out the dough on a floured work surface. Use a 5cm biscuit cutter with scalloped edges and cut out about 60 cookies. Place on baking trays. Place 1 teaspoon of the topping on each cookie.
Bake for 12–15 minutes until golden brown. Place on a wire rack and sprinkle with lemon rind while still hot.