Bun Dough:

1. In your stand mixer bowl, combine lukewarm milk, yeast, and a pinch of granulated sugar. Gently whisk together, then leave undisturbed for 5 minutes until the mixture gets foamy.
2. Add butter, sugar, eggs, egg yolks, and 2 cups (240g) flour. Attach dough hook, then knead on low until things just begin to come together.
3. Add remaining 2 ½ cups (300g) flour and kosher salt. Mix on low until the dough starts to come together. Increase speed to medium and knead dough for about 20–25 minutes. Dough is ready when it’s smooth, elastic, and shiny.
4. Tip dough out onto a clean work surface and form into a ball. Lightly grease a large bowl with neutral oil or baking spray. Form dough into a ball and place into bowl and roll around to coat all sides with oil. Cover bowl with beeswax wrap or cling film, then place in a warm, dry spot and leave undisturbed until dough has doubled in bulk, 45–60 minutes.
5. After the first bulk fermentation, gently punch down your dough to release excess gas build-up.
6. Cover bowl again with beeswax wrap or cling film and place in fridge to proof overnight. ^[3]

Speculoos Filling:

1. In the bowl of a stand mixer fitted with paddle attachment, beat together softened butter, sugar, speculoos blend, and kosher salt.
2. Transfer speculoos filling to a lidded container and store in fridge overnight. We’ll see you back here tomorrow!

Assembly & Baking:

1. Welcome back! Grease and line two 9" x 13" baking dishes. Set aside.
2. Retrieve dough and speculoos filling from fridge. Allow dough to warm up slightly, then punch it down to release excess gas build-up.
3. Tip dough out onto a lightly floured surface. Roll dough into a 16" x 20" rectangle. Using an offset spatula, spread softened speculoos filling onto dough, leaving a bare 0.25" border.
4. Stand with one of the 20-inch sides closest to you. Lightly brush opposite bare edge with water. Starting with the long edge closest to you, gently—yet tightly—roll dough up into a log. Pinch moistened seam and ends to seal.
5. Using unflavoured dental floss (or a serrated knife), cut log into 1.5" pieces.
6. Place buns into prepared pans and cover with beeswax wrap or cling film. Place dishes in a warm, dry spot and leave undisturbed for 45–60 minutes until buns have doubled in bulk.
   NOTE: Wondering if your buns have proofed enough? Give one a wee poke with your finger. If indentation springs back slowly, buns are ready to be baked. If the indentation springs back quickly, buns need to continue proofing.
7. During the second rise, heat oven to 350°F.
8. Bake for 30 minutes or until golden brown.(Internal temperature should be 190–200°F.)
9. While buns are baking, make the glaze. In a bowl, whisk together all glaze ingredients until smooth.
10. Once rolls are baked, transfer pan to wire rack and allow rolls to cool slightly. Drizzle glaze over rolls, sprinkle with a wee bit of flaky sea salt (or another topping), and serve warm!
    NOTE: If you want to bake these rolls the night before serving, go ahead and bake ‘em, but don’t glaze ‘em. In the morning, heat up the rolls in a 300°F oven for 5-ish minutes. Once rolls are warmed up, drizzle glaze over rolls for a perfect morning treat.