Heat the oven to 375. Grease a 10" cast iron skillet (or 8" x 8" baking dish) with one tablespoon of butter. Set aside.
Toss the blueberries with the honey, cornstarch, and lemon juice. Set aside to macerate while you prepare the cobbler topping.
Place the sugar, oat flour, cornmeal, almond flour, baking powder and salt into the bowl of a food processor. Pulse 2-3 times to blend the dry ingredients.
Sprinkle the butter cubes into the dry ingredients and pulse, pausing every 4-5 pulses, until the mixture is coarse and and chunky.
Add the eggs, vanilla extract, and lemon zest and pulse until just barely mixed into the dry ingredients. The batter should be thick and lumpy.
Pour the blueberries into the buttered skillet. Spoon the cobbler topping onto the blueberries. Space the heaps evenly, but there is no need to smooth them out.
Transfer the skillet to the oven and baked for 25-30 minutes until the topping is golden brown and crispy and the blueberries are bubbling. Remove from the oven and allow rest for 5-10 minutes. Spoon onto plates or into bowls and top with homemade whipped cream or ice cream.