For the sponge dough, combine Water (70 milliliter), Instant Dry Yeast (1/2 teaspoon), and Brown Sugar (1/2 teaspoon) in a mixing bowl. Mix in Bread Flour (105 gram) and knead with your hands for few minutes until smooth and shiny.
Roll into a ball and place in a greased bowl. Cover with cling film and let it rise for 1 hour in a warm and dark place.
After 1 hour, place dough into the refrigerator for at least 8 hours or up to 16 hours. Before using, take the sponge dough out of the refrigerator and return to room temperature.
Put Salt (1 teaspoon), Bread Flour (165 gram), Rye Flour (80 gram), Instant Dry Yeast (3/4 teaspoon), Brown Sugar (1 1/2 tablespoon), Olive Oil (20 gram), Water (125 milliliter), Cream (100 gram), Toasted Sunflower Seeds (3 tablespoon) and sponge dough into the bowl of a stand mixer. Using the dough hook, knead until the dough comes together, becoming elastic and tacky but not sticky, around 12-15 minutes at medium speed.
Place the dough in a large greased bowl, covered with cling film or a kitchen towel. Let the dough rise in a warm place for 1 hour, or until double in size.
Punch down the dough to release the air. Transfer the dough to a clean floured surface and divide into 3 equal portions. Roll out each dough into a long rectangle shape. Roll up each piece until a small log is formed.
Spread the Raw Sunflower Seeds (2 tablespoon) and Chia Seeds (2 1/2 teaspoon) on a flat surface. Dab or spray the dough surface with water and roll it through the sunflower seeds. Transfer the dough to a loaf pan lined with parchment paper. Let it rise for another 45 minutes-1 hour, or until double in size.
Bake at 350 degrees F (180 degrees C) for 25-30 minutes, or until golden brown.
Remove bread from oven and let cool on a wire rack.