Buckwheat Pizza With Mushrooms And Bone Marrow

Name: Buckwheat Pizza With Mushrooms And Bone Marrow
Ingredients: 1/2 cup tomato passata (puréed tomatoes); 1 clove garlic; 10 1/2 ounces button mushrooms; Himalayan salt and freshly ground black pepper; 1 pound 2 ounces grass-fed beef thigh bones filled with marrow (Ask your butcher for these); 1/4 cup salsa verde; 2 large handfuls baby beetroot or rocket leaves; 1 cup buckwheat flour; 1 1/2 tablespoons arrowroot; 1/4 teaspoon baking soda; 1/4 teaspoon Himalayan salt; Scant 1/2 cup water; 1 tablespoon olive oil; 1 teaspoon apple cider vinegar (unpasteurized)