In a standing mixer with a dough attachment (or using a bowl and wooden spoon) combine the warm water, yeast, and brown sugar. Let sit until the mixture is foamy, about 10 minutes. Add the butter, 4 cups of flour, and salt. Mix, adding more flour 1/4 cup at a time until the dough is smooth and slightly tacky (up to 4 1/2 cups total - I usually only need 4). Knead for 5 minutes in the mixer or by hand.
Shape the finished, kneaded dough into a ball, and cover with a tea towel. Place in a warm spot for about 30-45 minutes, or until the dough is doubled in size.
While the dough is rising, combine the 8 cups of water and baking soda in a large pot. Bring to a rolling boil. Preheat the oven to 450* F. Line two baking sheets with parchment paper, and lightly brush with oil. Whisk the egg with 1 Tablespoon of water, and set aside.
Once the dough has risen, cut it into 8 equal sections (about 2.75 ounces each). These will yield large pretzels, so you can easily divide it into 12 sections if you want smaller pretzels. On a lightly floured surface, roll each section into a 24-inch rope. Make a U-shape with the rope. Twist the ends of the rope together, and then fold the twist over, pressing the ends into the bottom of the U. (I highly recommend viewing the video above a few times before attempting). If you want a heart shape, pull the bottom of the U down to make a V-shape!
Working one at a time, drop a pretzel into the boiling baking soda water for 30 seconds (I push the pretzel into the water to get the whole thing coated). Remove with a slotted spoon, letting as much excess water drip off as possible. Place on the prepared baking sheet, and repeat with the remaining pretzels.
Brush the pretzels with the egg wash. Sprinkle the pretzels evenly with coarse salt and the seed mixture. Bake for 10-15 minutes, until a deep golden brown crust has formed. Serve warm with bleu cheese mustard. You can store these in an airtight container for up to four days, although they will get harder over time.