Make the ketchup

1. In a large saucepan, heat the vegetable oil over medium heat. When it’s warm, add the onion and garlic and sauté, stirring often, for 5 minutes. When the onion starts to become translucent, add the tomato paste, curry powder, paprika, cayenne, cinnamon, and allspice. Stir to combine and cook for 1 minute.
2. Add the diced tomatoes, maple syrup, and vinegar and season with the salt and black pepper. Bring the sauce to a simmer, then reduce the heat to medium-low and cook, uncovered, for 30 to 35 minutes, until reduced and thickened. Give the ketchup a stir every few minutes so it doesn’t catch.
3. Remove from the heat and pulse in a blender until smooth (or puree directly in the pot using an immersion blender). Let cool completely, transfer to a jar, and refrigerate overnight so all those flavors can really get to know each other.

Make the buns

1. In the bowl of a stand mixer fitted with the dough hook, combine the flour, yeast, sugar, salt, and water. Crack in five of the eggs and beat on low speed for 3 to 4 minutes, until all the ingredients are combined, scraping down the sides of the bowl as needed. Knead the dough for 3 minutes more to make sure those ingredients are getting extra cozy.
2. Cut the butter into 1/2-inch cubes. With the mixer running on low, add the butter one piece at a time, until it works itself into the dough. This will take a few minutes. Perfect time to grab a coffee, check your e-mail, or stage a sweet Instagram snap. The dough will be quite wet at this stage, but fear not!
3. When all the butter has worked itself into the dough, turn the mixer to high and let it go to town, kneading the dough for 10 minutes. The side of the bowl should be clean, and the dough ball should be making a slapping sound against it.
4. Transfer the dough to a lightly oiled large bowl, cover, and let rise slowly in the fridge overnight.
5. The next day, let the dough sit out for 30 minutes or so to come to room temperature. Line two baking sheets with parchment paper.
6. Lightly dust a work surface with flour and place the dough on it. Using a kitchen scale, divide the dough into sixteen equal 3.15-ounce pieces (if need be, make 14 or 15 balls instead to get them to the right size). Using the palm of your hand, roll a piece of dough on the floured surface in a clockwise motion for about 1 minute. A perfect little dough ball will naturally form as it rolls on the counter. Pinch off the bottom of the dough ball to close it if necessary. As you finish each ball, place it on one of the prepared baking sheets, leaving at least 1 1/2 inches between each ball.
7. Cover the baking sheets with plastic wrap and let the dough rise until doubled in size, about 1 hour.
8. Preheat the oven to 350°F.
9. Crack and beat the remaining egg in a small dish. Brush the top of each dough ball with the egg, covering all sides. Repeat with a second coat of egg. You can either top each bun with 1 teaspoon sesame seeds or leave them plain. Choose your own adventure.
10. Bake for 30 to 35 minutes, until deeply golden brown. Let cool on a wire rack for a few minutes before serving. These brioche buns are best eaten the same day, but will keep in an airtight container at room temperature for 2 to 3 days.

Make the burgers

1. In a large bowl, combine the ground chuck and sirloin and mix gently but thoroughly. Divide into eight equal portions and shape them into burger patties (see opposite for tips). Season both sides with salt and pepper and refrigerate for 30 minutes.
2. Preheat the oven to 350°F.
3. Heat a large skillet over medium heat. Split and toast the buns in the pan until toasty and golden brown. Set aside.
4. Remove the burgers from the fridge and place a thumbprint in the center of each patty. Smear 1 teaspoon of the mustard on both sides of each patty (best burger crust ever). Melt the butter in the preheated pan and, working in batches, fry the burgers for 3 to 4 minutes on each side, until a dark brown crust begins to form. The result: perfectly juicy medium-cooked burgers. For folks who prefer their burgers a little more well done, fry for 5 to 6 minutes per side.
5. Transfer the patties to a baking sheet as they’re done. Top each with cheese and place in the oven to melt, 2 to 3 minutes.
6. Build the burgers on the toasted buns with 1 or 2 burger patties, a slice of tomato, pickles, a slice of red onion, and lettuce. Top each with ketchup or mayo. Or both. Serve immediately.