Combine the milk, starter, flours, brown sugar, and eggs in the bowl of a stand mixer. Mix with a dough hook for 6 minutes on medium speed.

Slice the butter into one-inch cubes and add one cube at a time, mixing until the cube dissolves completely. Add all the cubes like this then continue to mix for 3 minutes on medium speed. Cover the bowl and let sit for ten minutes.

Add the salt and mix on medium speed for 2 minutes. Cover and let rise for two hours on the counter. Set in the fridge for 24-36 hours.

You can make this a day in advance of assembly. Put the diced peaches and sugar in a small saucepan over low heat. Allow to cook down for 30 minutes or until thick and jammy. You want it really, really thick, with barely any liquid. At the end of cooking, add the lemon juice and cook for a few more minutes. Let cool completely, then place in the fridge until assembly.

You can make this a day in advance of assembly. In a medium-sized bowl, combine the flour, cornmeal, sugar, and salt. Slice the butter into pats and add to the flour mixture. Pour in the almond extract, then toss and pinch the butter pieces with your fingers until they are the size of jellybeans and everything is crumbly. Cover and set in the fridge until ready to assemble.

Make this right before assembly. Add all the ingredients to the bowl of a stand mixer and mix with the paddle attachment on medium speed until fully combined. Pull out the marzipan filling and place it between two parchment paper sheets to roll out to a 9x12-inch rectangle.

Thoroughly oil a 9-inch non-stick loaf pan or Pullman pan with parchment paper.

Take the dough out of the fridge and roll out into a 9x12-inch rectangle. Pull off the parchment paper from one side of the marzipan filling and place on top of the dough rectangle. Remove the other side of parchment paper.

Using 280g of the peach filling, spread it over the marzipan layer with an offset spatula until evenly coated. Then roll up the dough in a way that it is 9 inches wide. With a sharp, serrated knife, slice the cylinder in half lengthwise, then braid the two pieces up and over each other like a babka, with the jammy part facing up/out.

Carefully lift the braid and place it into the prepared pan, scooping the ends of the dough underneath if necessary. Cover loosely and let rise for 2.5 hours or until it just reaches the top of the pan. Preheat the oven to 375F thirty minutes before the rise is over.

Place the loaf pan on a sheet pan to catch any crumbs during the bake. Sprinkle all of the crumble topping on top of the risen dough. Bake for 40 minutes, then lower the heat to 350F and cover with foil, baking for 20 minutes more. Then remove the foil and bake for 10 more minutes.

Let cool in the pan for 30 minutes, then run a knife along the inner edges of the pan to pry off any pieces of crumble that are gluing your loaf to the pan. Carefully pull the bread out and let cool completely on a cooling rack before slicing. If it’s stuck, wait 15 more minutes and retry. This is a top-heavy loaf so be careful when moving it around/touching it while still hot.