Mix the dry ingredients: In a medium bowl, whisk together gluten free flour, tapioca starch, cornstarch, and kosher salt until well blended. Set this mixture aside.

Prepare the wet ingredients: In a separate large bowl, beat room-temperature eggs until they’re pale and foamy. Slowly add room-temperature milk, whisking to combine. Gradually add the dry mix, stirring until the batter is completely smooth.

Let the batter rest: Pour the batter into a measuring cup for easy pouring later. Let it sit uncovered at room temperature for 25–30 minutes while you preheat your oven to 450°F. Place your oven rack in the lower third position for best heat distribution.

Preheat your pan: Set your popover or muffin pan on a baking sheet and place it in the oven for 5–10 minutes to preheat. This step is crucial for getting a quick rise. Lightly grease the pan with non-stick spray once hot.

Fill the pan and start baking: Carefully fill each cavity about two-thirds full. Bake at 450°F for 15 minutes without opening the oven. Then lower the oven temp to 400°F, baking for another 10 minutes. Finally, reduce again to 350°F and bake an extra 5–10 minutes until the tops are deep golden brown and fully puffed.

Finish with steam release: Once about 30 minutes of total baking time has passed, open the oven and gently prick each popover with a wooden skewer or knife to let trapped steam escape. Close the oven and bake 2–3 minutes more to ensure a firm shell.

Cool and serve: Remove the popovers from the oven and allow them to sit in the pan for 1–2 minutes to set. Then transfer them to a rack and serve warm. These gluten free popovers are best enjoyed fresh!