Preheat the oven and line a baking sheet with parchment paper or a baking mat
As I mentioned above, you want to keep your butter, cream, and eggs COLD until you are ready to use them. That being said, grab a large bowl and whisk together your flour, brown sugar, baking powder, baking soda, and salt. Set aside.
In a small bowl, combine the rosemary, diced ham, and Parmesan cheese and toss. Place bowl in refrigerator until needed.
Grab that stick of frozen butter from the freezer and a box grater. Grate the frozen butter on the large side of the grater. I don't own a food processor but one will do the job, too. Add the butter into the bowl of dry ingredients and toss gently with a fork.
In a small measuring cup whisk together the heavy cream (whole milk will work, too) and one egg. Pour into flour/butter mixture and gently combine until you have a rough dough ball. You may need to add up to 2 tablespoons more of cream.
Add the rosemary, ham, and cheese and gently fold into the scone dough. Turn the dough out onto a lightly flour surface and pat into a large ball. To make sure the dough doesn't get too tough, I like to cut the dough in half. Pat half the dough into a 8 inch circle, about one-inch thick. You can either cut the dough into equal wedges or do as I did and use a biscuit cutter.
Pro Tip: when using a biscuit cutter, cut straight down and resist the urge to "twist" the cutter. Twisting the biscuit cutter will "seal" the edges, which keeps your biscuits from rising high.
Place cut scones onto prepared baking sheet, about an inch or so apart. If you saved additional ham and cheese, sprinkles some of each on the scones before baking. Lightly press the ham on. Bake for 18-20 minutes, or until the tops are lightly golden brown. Remove from oven and allow to cool on wire rack for a few minutes. Best when served warm, but equally delicious at room temp. Store scones in refrigerator for up to 3 days.
Freezer Tip: Flash freeze baked scones for up to 2 months. You can cut and freeze the scone dough for 2 months. Add a minute or two onto the bake time if baking from a frozen state.