Grate the cheese and let it sit out along with the butter for at least 30 minutes.
Place the grated cheese and the butter in the bowl of a stand mixer or in a deep bowl if you want to use a hand held electric mixer. Use the paddle attachment and begin to blend together on low speed. Once the cheese and butter starts to combine, increase the speed to high and beat until the mixture is smooth and thick like a whipped cream or mousse. Scrape down the sides of the bowl as needed.
Preheat the oven on 350℉/175℃. Sift the flour into a bowl and mix in the seasoning blend. Add ¼ of the flour at a time to the cheese mixture and blend on low speed until incorporated. Repeat until all the flour is used.
Line cookie sheets with parchment or lightly coat with butter or cooking spray. Place 1 Tablespoon of the cheese mixture onto the cookie tray for each cookie. Spread them out by about 3" to allow enough room for them to expand as they bake. Repeat until the cookie trays are filled. I use this scoop and love it: Pampered Chef Small Scoop
Gather the toppings you want to use. Using a tart shaper or the back of a spoon (or your thumb), press the ball of dough down and make a well in the center. You want the edges to be higher than the well so the filling doesn't leak around the edges.
Add about ½ teaspoon to the center of each cookie. Place the trays in the preheated oven and bake for 13-15 minutes or until the edges just start to brown.
Remove from the oven and place the cheddar cheese thumbprint cookies onto a cooling rack. Cool & Serve.