Preheat your oven to 425 degrees F. This is an important step to ensure that your biscuits rise perfectly and develop that golden crust. As the oven heats up, take a moment to gather your ingredients and get everything ready.
Brush a 9x13 inch baking dish with the melted butter. This will help the biscuits to not stick and add extra flavor to the bottom.
In a large bowl, whisk together the flour, baking powder, and kosher salt. Make sure to combine these dry ingredients thoroughly to ensure even distribution of the baking powder and salt.
Add in the cold butter cut into small pieces. Using a fork or pastry blender, work the butter into the flour mixture until it resembles coarse crumbs. This step is crucial for achieving that flaky texture.
Next, fold in the freshly grated Gruyere cheese and chopped fresh herbs. Gently mix until just combined, being careful not to overwork the dough.
In another bowl, whisk together the buttermilk and sour cream. This mixture will add moisture and richness to the dough.
Pour the wet ingredients into the dry ingredients and mix until just combined. It’s okay if the mixture is slightly lumpy—you don’t want to overmix it. That’s the key to tender biscuits!
Press the mixture into the buttered baking dish, ensuring it’s evenly spread out. Don’t worry about making it perfect; the rustic look is part of its charm.
Use a knife to score the dough, making cuts in a grid pattern. This will help you to cut the biscuits easily once they’re baked.
Bake for 30 to 35 minutes, or until golden and puffed. Keep an eye on them towards the end—oven temperatures can vary!
Once baked, let the biscuits cool completely in the dish before cutting and serving. This allows them to firm up slightly, making them easier to handle.