I followed the recipe for milk and butter toasted oat porridge sourdough from "Full Proof Baking" with some modifications.  Thank you to Kristen for the idea!

Characteristic of this bread:  The texture is moist with a hard crust and very mild tangy taste. Usually sourdough starter provides an aromatic flavour to the bread and with addition of toasted butter oat porridge, the bread has a more substantial flavour.

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Butter Toasted Oat Porridge Sourdough Bread Recipe
Yields:  1 loaf
Total flour 440g, including the flour from levain.
320g bread flour (I used Japanese high gluten flour) - 80% 50g whole wheat flour - 12.5%
30g rye flour - 7.5% 309g water - 80% hydration  (80% final hydration) 7g sea salt - 1.75%

80g sourdough starter (100% hydration) - 20%
Feed 30g sourdough starter + 30g bread flour + 30g water, keep at room temperature, wait until tripled, around 3 - 4 hours

Oat Porridge:
88g oat porridge - 22%
Toasted 48g rolled oat with 13g butter in a saucepan until slightly golden brown and aromatic, then add in 101g water + 101g fresh milk and simmer till become thick.  Keep aside to cool.

METHOD: Autolyse - Mix all flours and water, stir until there is no more dry flour with a spatula.  Or use a stand mixer with paddle attachment for 2-3 minutes at low speed.  Cover and leave for 1 to 2 hours. Levain - Wet your hand, add 80g levain into the dough and hand mixing until incorporated, about 3 - 4 minutes. Or use a stand mixer with hook attachment and knead for 6 to 8 minutes until window pane stage.  Cover and rest for 30 minutes. Sea Salt and Oat Porridge-  Sprinkle sea salt on top of the dough, use hand to mix in the salt.  It takes about 5 minutes until it is fully incorporated.  Immediately, add in 88g oat porridge, use your hand to break up the lump if possible and slowly knead in to the dough until well incorporated.  Cover and rest for 30 minutes. Fold - Lightly mist the counter top with water.  Wet your hand and scrapper.  Transfer dough to the counter top.  Pull and fold the four sides, flip over and round the dough.  Return to the same bowl.  Cover and rest for 30 minutes. Lamination -  Lightly mist the counter top with water and wet your hand.  Pull from centre out to form a rectangle shape. Pick up one edge and fold into the center.  Pick up other edge and fold into the center over first section.  Fold the top down half way.  Fold the bottom up.  Put dough in a new dish (square pyrex dish).  Cover and rest for 30 minutes. Stretch and Fold 1 - Fold dough in the dish. Cover and rest for 30 minutes. Stretch and Fold 2 - Repeat the same.  Cover and rest for 30 minutes Stretch and Fold 3 - Repeat the same.  Cover and rest for 90 minutes.  Shape - Flour the counter top.  Shape and coat the dough with sesame seeds then transfer to a  slightly flour banetton.   Proof - Proof at room temperature (RT) for 15 - 20 minutes.  Then retard overnight in the fridge for 12 - 16 hours. Preheat oven, with the dutch oven at 250C for 30 minutes before baking. Take bread dough out from the fridge, invert onto a parchment paper and scoring.  Immediately transfer the dough with the parchment paper to your preheated dutch oven. Bake with cover on for 20 minutes.  Remove the cover and lower the temperature to 230C, continue bake for another 20 minutes. Remove bread from oven and dutch oven. Let it cool on rack completely before slicing.
Butter Toasted Oat Porridge
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