Heat oven to 350F. Prepare 9 x 13" pan with baking spray and set aside.
In a medium/large bowl, whisk together flour, sugar, salt, baking powder, and pumpkin pie spice.
Add in milk, eggs, pumpkin and vanilla extract. Using hand mixer, whisk, or spatula, beat until smooth. Stir in melted butter
Place filling ingredients into bowl and using a pastry blender, spatula or knives, combine. Sprinkle on top of cake and swirl in using knife or spatula.
Bake for 30 minutes, or until toothpick/skewer inserted into center comes out clean. Cool for 15-20 minutes, or until just warm.
Combine glaze ingredients and drizzle or pipe over top of cake. Serve warm.
Notes
*If preparing this cake ahead of time, re-warm and add glaze right before serving.