Preheat the oven to 325°F and place the rack in the middle position. Prepare a 12-count mini Bundt mold by spraying generously with nonstick baking spray.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
In the bowl of your stand mixer fitted with a whisk attachment, add oil, butter, sugar, and honey, and mix for 2 minutes on high speed until pale and fluffy.
Add the eggs and mix well, scraping down the sides and bottom of the bowl.
Reduce the speed of the mixer to low and add dry ingredients. Then add sour cream, milk, and vanilla until just combined. Do not overmix.
To portion the batter evenly, you can use a heaping #40 scoop or scant ¼ cup measure. Evenly divide the batter among the prepared molds and fill about 2/3 of the way. You will have about 6 servings leftover to bake in a second batch.
Place cakes in the oven and bake for 20-22 minutes, until an inserted toothpick comes out mostly clean and the edges of the cake have browned lightly and begun to pull away from the sides of the mold.
Remove from the oven and cool in the pan for 10 minutes. Then invert onto a wire rack to cool completely, about 20 minutes. Once the first batch is cooling on the wire rack, spray the molds again with nonstick spray and repeat filling, baking, and cooling with the remaining batter.