In the bowl of a stand mixer, whisk together the pineapple juice, milk, honey, egg, and sourdough discard until smooth.
Add 4 ½ cups (540g) flour, yeast, and salt. Mix on low speed until a shaggy dough forms. It will look rough and slightly sticky at this stage.
Add the softened butter one tablespoon at a time, mixing on medium-low speed. The dough may look like it’s falling apart or not coming together at first. This is normal—keep mixing and let the dough absorb the butter.
Continue kneading for 8–10 minutes. The dough will go through a sticky, messy phase before becoming smooth and elastic. Avoid adding extra flour too early, even if it looks too soft.
The dough should be soft and slightly tacky and mostly pulling away from the sides of the bowl.
To check readiness, stretch a small piece of dough. It should stretch thin enough to let light through without tearing immediately.
Only if the dough is still very loose after kneading, add flour 1 tablespoon at a time.
Transfer the dough to a lightly greased bowl, cover, and let rise for 60–90 minutes, or until doubled in size.
Turn the dough out onto a lightly floured surface and divide into 15 equal portions (about 65–70g each). Shape into smooth balls, keeping the tops tight.
Arrange in a greased 9x13-inch pan. Cover and let rise for 45–75 minutes, until puffy and touching.
Preheat oven to 350°F.
Whisk together the egg and milk, then gently brush over the tops.
Bake for 18–22 minutes, rotating halfway through, until golden brown and the center reaches 190°F.
Let cool slightly before serving.
Notes
Storage Information: Store in an airtight container at room temperature for up to 3 days. Reheat at 300°F for 8–10 minutes to refresh softness.Make Ahead: After shaping, cover the pan and refrigerate overnight. The next day, let the rolls sit at room temperature for 1 to 1½ hours until puffy, then bake as directed.Slider Bun Option: Divide the dough into 18–20 portions instead of 15. Arrange in the same pan and allow to rise until puffy and touching. Bake at 350°F and begin checking around 16–18 minutes, until the internal temperature reaches 190°F. Perfect for pulled pork sliders, mini burgers, deli sandwiches, or breakfast sandwiches.Tips:
Use recent sourdough discard for best results. Very old discard can affect both flavor and structure.
Do not add too much flour too early. The dough will look sticky after adding butter—this is normal. Let it fully knead before making adjustments.
Start with less flour if using higher-protein flour (such as Costco organic or bread flour), as it absorbs more liquid.
The dough should feel soft and slightly tacky, not dry. This is key for a fluffy, tender roll.
Smooth, tight shaping will give you the best final appearance.
Rotate the pan during baking for even browning.
If the tops brown too quickly, loosely tent with foil.
To use active dry yeast instead of instant yeast, bloom it in the warm milk and pineapple juice with a pinch of sugar for 5–10 minutes before mixing.
This recipe was tested with canned pineapple juice (such as Dole). Fresh pineapple juice has not been fully tested and may affect the dough due to natural enzymes.