Remove the roots and about 2 inches of greens from the top. Remove outer layer of onions and rinse. Roughly chop.
To prepare scones:
Preheat oven to 400 degrees.
Cut frozen butter into small pieces using a butcher knife. (I usually cut in quarters lengthwise, then chop by Tablespoons, roughly)
Measure flours, baking powder and salt and pepper into the bowl of a food processor, add butter.
Pulse together until butter becomes pebbly and mixture looks like rough sand.
In a glass measuring cup, measure cream and add the egg. Beat to combine.
Add cream mixture to the food processor, pulse until combined.
Add onions and cheddar cheese, pulse until combined.
Pour pebbly dough onto a baking sheet lined with a silicone sheet or parchment paper. Squeeze together to form a disk about 7-8 inches in diameter and at about an inch thick. (As you pour out your pebbly dough, you may think that it will never come together, but it will! Just squeeze together and press. If you really feel it is too crumbly, dribble a tiny bit of cream into the dough but I doubt you will need it.)
Using a sharp knife, cut into eight triangles (cut across the diameter one way, then the other, then on the diagonals.)
Separate triangles and set at least 1-inch apart on the baking sheet.
Bake until lightly brown, about 15 minutes.
To prepare the Thyme Mustard Butter:
Combine all ingredients (butter, salt, pepper, thyme leaves and mustard). Mix until thoroughly combined. Will keep in the refrigerator for at least a week.
To prepare the Tarragon Mustard Vinaigrette for the Salad Greens:
In a small jar that has a tight lid, combine mustard, vinegar, olive oil, tarragon and green onion. Screw on top tightly and shake until fully emulsified. (The olive oil is no longer separate from the vinegar but thoroughly combined.) Or, you can whisk together in a small bowl.
Taste and season with salt and pepper to taste.
Pour over 4 large handfuls of greens and toss to combine.
Notes
Use leftover vinaigrette over steamed vegetables.
Recipe by FamilyandForks at https://www.familyandforks.com/spring-onion-cheddar-scones-thyme-mustard-butter/