Preheat the oven to 300 degrees F (150 degrees C). Line 2 rimmed baking sheets with parchment paper.
Combine walnuts and honey in a jar, cover, and set aside.
Combine oats, groats, buckwheat flakes, almonds, hazelnuts, sunflower seeds, cinnamon, nutmeg, allspice, and ginger in a bowl; toss until completely mixed.
Stir together olive oil, coconut sugar, and brown rice syrup in a small saucepan over low heat until combined. Cook until heated through, about 5 minutes. Remove from the heat and stir in vanilla extract. Pour over the dry mixture and mix until evenly combined; spread over the prepared baking sheets.
Bake in the preheated oven for 25 minutes. Stir, rotate baking sheets, and bake for another 15 minutes. Stir, rotate again, and bake until golden brown, about 15 more minutes. Sprinkle coconut, flax seeds, and raisins over the granola and toss to mix. Turn the oven off, but leave trays inside and prop the oven door open with a wooden spoon for 10 minutes. Remove from the oven and allow to cool.
Place 1/2 cup yogurt in a deep single-serve bowl. Top with a scant 1/3 cup granola, 1/4 cup raspberries, and 1/8 cup walnut-honey mix. Repeat to assemble remaining bowls.