1) Preheat oven to 375 degrees.
2) Place all the ingredients in a food processor and pulse a few times until the walnuts and cauliflower become crumbly. Be careful not to over-process the mixture or else it will lose its crumbly texture and be too smooth. The texture should resemble that of crumbly ground beef.
3) Spread the mixture into a single layer onto a parchment lined baking sheet. Use two baking sheets if necessary.
4.) Bake for 30 minutes, stirring halfway through to prevent over-browning. The cauliflower-walnut crumble is done when it’s dry, crumbly and brown.
5) Store any leftover crumble in an airtight container in the refrigerator for up to 1 week. For longer storage, freeze in an airtight container for up to 3 months.
6) Can change seasonings for Italian flavor. Omit chili powder and cumin. Add 1 teaspoon each of oregano, basil, and ground fennel seeds.