Apart from the ingredients below you will need a medium sized bowl with about 3 cups of flour to toss your dough in (explained below) and a cookie scoop. For reference I use this one.
Ideally for the butter you have a scale but you can measure out 6 Tablespoons and for the 1 1/2 teaspoon just cut 1 Tablespoon in half. (1 1/2 teaspoons + 1 1/2 teaspoons = 1 Tablespoon)
2 + 1/2 cups all-purpose flour
1 + 1/4 cups cake flour
1/4 cup + 2 Tablespoons sugar
1 Tablespoons + 1 3/4 teaspoon baking powder
1Tablespoons + 1/4 teaspoon salt
3.25 ounce butter (approximately 6 Tablespoons and 1 +1/2 teaspoons)
plus 3 Tablespoons melted butter for brushing
1 1/2 - 2 cups buttermilk (plus more for brushing)
Adjust oven rack to middle position and heat oven to 375º.
Cut the butter into playing-dice sized cubes and keep cold in the refrigerator.
Melt the 3 Tablespoons of butter. Brush the inside of a 9-inch round cake pan with the melted butter and set aside.
Pulse the flours, baking powder, sugar and salt in a food processor to combine. Scatter butter cubes evenly over dry ingredients; pulse until mixture resembles pebbly, coarse cornmeal, about 7 quick pulses.
Transfer mixture to medium bowl. Add buttermilk to dry ingredients and stir with rubber spatula until just incorporated (dough will be very wet and slightly lumpy).
Using a cookie scoop, scoop a level amount of dough; drop into the bowl with flour. Repeat with 4 more times. I don’t like to crowd the bowl with dough so I go 4 biscuits at a time. Gently pick up each piece of dough and coat with flour; gently shape dough into a hockey puck-like shape, shake off excess flour, and place in prepared cake pan. Repeat with remaining dough, arranging around the perimeter of the cake pan first then in the center. Brush biscuits with buttermilk, taking care not to flatten them. Bake until they are dark golden on top- about 25 minutes. All ovens are different so start checking around 20 minutes.
When they are done and out of the oven, brush the biscuits with melted butter. Cool in pan 5 minutes, then invert biscuits from pan onto clean kitchen towel; turn the biscuits right-side up, break apart and serve.