Cauliflower Korma with Blackened Raisins

Name: Cauliflower Korma with Blackened Raisins
Ingredients: 2 large heads cauliflower, broken into bite-size florets; Canola oil; 2 1/2 teaspoons kosher salt, divided, plus more to taste; 2 large yellow onions, thinly sliced; 6 garlic cloves, grated; 1 (2 1/2-inch) piece fresh ginger, peeled and grated; 2 teaspoons garam masala; 1 teaspoon freshly ground black pepper; Pinch of ground cardamom; Pinch of cayenne pepper; 1 cup ground almonds; 2 tablespoons honey; 2 cups plain whole-milk Greek yogurt; 3/4 cup whole milk; 1/2 cup raisins; 1/2 cup sliced almonds