Step 1

Add the milk, tea bags and vanilla to a medium saucepan and bring to a gentle simmer. Once heated through, remove from the heat, cover and let the milk steep and cool for 30 minutes. Strain the milk into a jug (pitcher), squeezing the tea bags, then set aside.

Step 2

In a large bowl or the bowl of a stand mixer, mix together the flour and sugar. Add in the salt and yeast to separate sides of the bowl, make a well in the centre and pour in the beaten egg and cooled milk. If using a stand mixer fitted with a dough hook, mix for 6 minutes on low speed. If mixing by hand, knead in the bowl for 10 minutes (the dough will be quite sticky at first, but try not to add too much extra flour). Let the dough rest, uncovered, for 5 minutes, then knead for a further 4 minutes until you have a smooth dough. Add the softened butter and knead for a further 5 minutes until you have a shiny, supple dough.

Step 3

Place the dough into a lightly greased bowl, cover with plastic wrap or a clean dish towel and leave to prove in a warm place for 1–2 hours or until nearly doubled in size.

Step 4

Meanwhile, make the filling. Mix the caster sugar and lemon zest together in a bowl, using your fingertips to rub the zest into the sugar until it resembles wet sand. Add the softened butter and mix until thoroughly combined. Set aside.

Step 5

Preheat the oven to 200C (180C fan/400F/gas mark 6). Line the base of a 20-cm (8-in) springform or loose-bottomed cake pan with baking paper and grease the sides.

Step 6

Once the dough has risen, use your fingertips to press it down and knock the air back. Turn it out onto a lightly floured surface and roll it into a large rectangle, about 3–4mm (⅛in) thick. Spread the filling mixture evenly across the surface. Starting from one of the longest sides, roll the dough up tightly and slice into 7 equal rolls. Arrange the rolls in the prepared pan, leaving a bit of space between them, and cover the pan loosely with a dish towel. Leave to prove for 25–35 minutes, or until the rolls are puffy and touching each other.

Step 7

Top with pearl sugar, if using, and bake for 35–40 minutes until a deep brown color.

Step 8

While the buns bake, make the syrup. Add the water, sugar and tea bags to a small saucepan, bring to the boil and let simmer for 1 minute. Remove from the heat and set aside.

Step 9

When the buns are baked, let them cool for a few minutes before brushing them generously with the chamomile syrup, letting it seep through. Let them cool completely before serving.