Perfect Homemade Biscuits

You know how I usually go out and find a recipe and then modify it? Well, this morning I went looking for a new biscuit recipe for breakfast, and found a recipe that already had so many variations that I had trouble finding one of my own to try.
I did, but it was work.
I found This recipe at https://www.momontimeout.com/perfect-biscuits-every-time-recipe/ and it has distinct advantages over either my buttermilk biscuit recipe from the now-defunct Meemo's Kitchen, or even baking mix biscuits. It doesn't take anything I don't usually have in my pantry or refrigerator, it's as fast to make as baking mix biscuits (nearly) and it is easily modified. The stock recipe comes out very soft, and rather flaky. I'll include some suggested changes at the end of the instructions.
Here's the recipe for Perfect Homemade Biscuits!

Ingredients

• 3 cups all-purpose flour
• 3 tbsp sugar
• 1/2 tsp salt
• 4 tsp baking powder
• 1/2 tsp cream of tartar (optional)
• 3/4 cup COLD butter
• 1 egg (optional)
• 1 cup whole milk (skim works too)

Instructions

• Preheat oven to 450 degrees.
• The secret to excellent biscuits is COLD BUTTER. Really cold. Many times the biscuit dough gets worked so much that the butter softens before the biscuits even go in the oven. Try cutting the butter into small pieces and stick back in the fridge pulling out only when ready to incorporate into the dough.
• Combine the dry ingredients in a large bowl. 
• Use a pastry cutter to cut cold butter into flour mixture. Don't go too crazy here - you want to see small, pea-sized pieces of butter throughout the dough. 
• Add in the milk and egg and mix just until the ingredients are combined. The dough will be sticky but don't keep working it. You should be able to see the butter pieces in the dough.
• Turn the dough out onto a generously floured surface. Sprinkle some flour on to the top of dough so it won't stick to your fingers and knead 10-15 times. If the dough is super sticky just sprinkle on some additional flour.
• Pat the dough out to 3/4 - 1 inch thickness and cut with a biscuit cutter or glass. I ended up with nine this time but depending on who is snacking on biscuit dough, I can get up to 12 biscuits. [I got 12 on my first batch, 14 on my second, and who snacks on raw biscuit dough?-Edly]
• Place the biscuits on a lightly greased baking sheet or parchment lined baking sheet and bake for 10 to 15 minutes or until golden brown on top.
• For extra yumminess, brush the tops of the biscuits with melted butter... [Your arteries will slam shut in delight!-Edly]

Modifications and notes:

Some of the ingredients are considered optional by the source.  They claim it is safe to leave out the cream of tartar, and that the egg is optional. They also say you can use buttermilk instead of whole milk, but you will have to use more because of how thick it is. UPDATE 12/20/2020: They're right about it taking more buttermilk. Today I made this recipe with the following modifications: 1 cup buttermilk instead of milk (I could have used a bit more.) 1 tablespoon of baking powder and 1 teaspoon baking soda instead of 4 teaspoons baking powder (1 tablespoon is 3 teaspoons, and buttermilk is slightly acidic, which activates the baking soda.) No cream of tartar (I couldn't find any.)

The first time I fixed them today (I made them for breakfast and dinner both) I made them exactly as outlined in the recipe above, only choosing not to brush the biscuits with additional butter after baking (there's so much butter in them already!) The second time I added about 2 tablespoons of plain yogurt to the one cup of skim milk I almost always use in my cooking. They came out a bit moister that way.

Either way, these are best eaten hot and straight from the oven. They are not nearly as good if allowed to cool.
After testing: You can make these biscuits ahead of time and freeze them before baking them, just like Pillsbury frozen biscuits. Place the already formed biscuits into a baking sheet and place it into the freezer for an hour or two, then put the frozen biscuits into a freezer bag and store them for up to several weeks and make them as you want them!