Prep: Preheat your oven to 350° F. Use a paper towel to liberally grease a 10-cup bundt pan with shortening, making sure to coat all the nooks quite well. Add a handful of flour and tap it into all the nooks of the pan, coating the shortening. Tap out the excess. If you see any bare spots, be sure to go back and get them with shortening + flour. This is my no-fail method to prevent cakes sticking in the pan!
shortening, all-purpose flour
Make the Crumble: Melt the butter in a medium mixing bowl. Stir in the remaining streusel ingredients. You should have a crumbly mixture. Crumble into small pieces on a parchment-lined pan and bake for 10-14 minutes, until deep golden brown. Prepare the peaches while this bakes - see step below. Set aside to cool. Break up the pieces further, as desired, while it cools, with a spatula.
1/2 cup salted butter, melted, 1 cup all-purpose flour, spooned & leveled or weighed out , 1/2 cup brown sugar, packed, 1/2 tsp cinnamon, pinch of salt
Make the Peach Filling: Add the sliced peaches, sugars, lemon juice, cinnamon, and nutmeg to a medium sauce pan over medium heat. Cook for 4-6 minutes (it will take a little longer if using frozen slices). The mixture will be quite bubbly. Stir the corn starch and water together in a small bowl and stir into the peach mixture. Cook for 1 minute, then remove from the heat immediately and stir in the vanilla. Transfer to a medium bowl to cool completely in the fridge.Make-Ahead Tip: This can be done up to 3 days ahead. Store in a jar in the fridge. 4 large ripe peaches, sliced , 1/3 cup brown sugar, packed, 3/4 tsp cinnamon, 1/4 tsp nutmeg, 1 tbsp corn starch, 1 tbsp water, 1/2 tsp vanilla extract
Start the Cake Batter: Beat the softened butter in a large bowl with an electric mixer on high speed for about 30 seconds, until creamed. Add the sugars and beat on high for 2 minutes. Add two eggs at a time, and beat on medium speed with each addition, for about 30 seconds or so, until combined. Mix in the oil until just combined. Add the vanilla and water and mix on medium until just combined. The batter may a look a bit split at this point - that's completely normal and it will be fine, don't fret! Mix in the sour cream on medium until just combined.
3/4 cup salted butter, softened at room temperature , 1 and 1/2 cups granulated sugar, 3 large eggs, at room temperature , 2 tsp vanilla extract, 1 tbsp + 1 tsp vegetable oil, 2 tbsp warm water, 3/4 cup full-fat sour cream, at room temperature, 1/4 cup light brown sugar, packed
Finish the Cake Batter: Add the flour, baking powder, salt, cinnamon, and nutmeg. Mix on low speed until the dry ingredients are about halfway mixed in. Then, add the milk and continue mixing on low speed until everything is almost combined. Gently fold any stray streaks of milk or flour in with a spatula.
2 and 1/4 cups all-purpose flour, spooned & leveled or weighed out, 2 and 1/4 tsp baking powder, 1/4 tsp salt, 1 tsp cinnamon, 1/2 cup milk, at room temperature, 1/4 tsp nutmeg
Assemble Cake: Add half the cake batter to your prepared pan (about 670 grams). Measure one cup of the chilled peaches (270 grams) and lay them in an even layer over the batter. Add the remaining batter and spread it evenly. Sprinkle on 1/2 cup of the streusel (80 grams).
Bake: Bake for 55-60 minutes. A skewer or knife inserted into the pan (be sure to use something longer than a toothpick, since bundt pans are quite deep) should pull out some moist crumbs, but not wet batter. Let the cake cool in the pan on a cooling rack for 30 minutes (the fruit layer in the middle means this bundt needs to rest longer than the usual 10 minutes). Then, loosen the edges with a butter knife and invert onto the rack to cool completely. Tip: It shouldn't stick, but if it seems to be sticking, keep the pan inverted over your rack and tap all around the pan firmly with a metal spoon or something similar to help knock out the cake. Make the Glaze: While the cake cools, whisk all the glaze ingredients together in a small bowl or glass measuring cup. Taste and add a splash more cinnamon if desired. The glaze should be a bit thick so it doesn't run right off the cake.
2 cups powdered sugar, 3/4 tsp vanilla extract, 1-3 tbsp milk , pinch of cinnamon
Serve + Store: The cake doesn't need to cool much more after the 30 minutes it had in the pan, but you can let it cool longer if desired. Top with the glaze, more peaches, and extra crumble! Slice, and enjoy immediately! Store leftovers in an airtight container in the fridge for 2-3 days.