- In food processor, pulse together flour, Cheddar cheese, Parmesan, oregano (or basil), salt and pepper until well combined. Scatter butter cubes over mixture; pulse until mixture resembles coarse meal. Add sour cream and egg yolk; pulse just until dough starts to hold together. Transfer dough to floured work surface; press into disc. Cover with plastic wrap and refrigerate until firm, about 1 ½ hours.
- Preheat oven to 375°F (190°C).
- On floured surface, roll out dough to ¼” (5 mm) thickness, re-flouring as necessary. Using cookie cutter, cut out rounds, re-rolling leftover pieces only once. Arrange rounds on parchment paper-lined cookie sheets.
- Bake in centre of oven for 13 to 15 minutes or until light golden.
- Let cool on pan. (Crisps can be stored in airtight container for up to 3 days.)
- If you don’t have a food processor, simply use pastry cutter or two knives to cut butter into flour. Then add White Cheddar, Parmesan, oregano (or basil) and pepper. Proceed as directed.