Preheat your oven to 350°F and grease your bundt cake pan.
In a large mixing bowl, combine your granulated sugar, brown sugar and oil.
One at a time, add all 4 of your eggs. Be sure each egg is fully mixed in before cracking the other.
With the mixer still going, spoon in your pumpkin and mix until fully incorporated.
In a separate medium size bowl, combine your gluten-free yellow baking mix, pumpkin spice and cinnamon. Lightly whisk together.
Alternating between your dry mix (baking mix + spices) and your milk, mix those into the wet mix (sugar, oil + pumpkin). Once it is fully blended, pour your mix into your greased baking pan.
Bake your bundt cake for 55 minutes, and allow to cool in the pan for 15 minutes after.