Combine the room temp buttermilk, eggs, and vanilla in a bowl. Mix it to break up the eggs and set it aside.
Put the flour, sugar, salt, baking powder in the bowl of your mixer. Let that combine in your mixer with the paddle attachment.
Add the softened butter and turn it on low for about 1 minute or until your dry mixture looks like a coarse sand texture.
With your mixer on low add about 1/2 of the wet mixture (just enough to make the whole mixture wet and look like a cake batter, not cookie dough). Let that mix on medium for 2 minutes. This is a part of the reverse creaming method. Don't go over or under 2 minutes. You want to develop structure for your cake but not develop the gluten because that will give you a tough cake.
After 2 minutes stop and scrape your bowl, turn it back on low and add the rest of the wet mixture. Let it combine 10-15 seconds or until combined. Scrape your bowl and make sure it's mixed evenly.
If the sides of your baking pans look like the baking spray ran down from sitting, quickly give them a spritz of baking spray trying not to coat your pretzel crust with it.
Divide your batter evenly among your pans, about 15 oz each.
Make 4-5 divets in the batter with a spoon and quickly spoon in some of the praline sauce. Marble that with a butter knife going back and forth a couple of times.
Add a bit of the left over pretzel crust and push it down a little into the batter with a spoon or knife.
Cover your cake pans with aluminum foil, and bake them at 330 degrees for about 60 minutes, or until done. Check to see if they are done by inserting a toothpick into the center of the cake. If it comes out dry it is done.
Once the cakes are done allow them to cool on a cooling rack for about 10 minutes or until the pans are cool enough for you to handle.
The pretzel crust will stay together best if removed earlier (so they don't steam). Once the pans can be handled, carefully run a knife around the edge (the sauce can cause it to stick some). Be careful when running your knife along not to break up the crust on the bottom. Carefully remove the cake from the tins and allow them to come to room temp on cooling racks. It's ok if a little of the crust on the edge breaks off, it's bound to happen. The cake must be fully cooled to move on to the next part. You may want to wrap them in plastic wrap and decorate the next day or freeze, then decorate when you're ready.