Preheat the oven to 400F; line a muffin tray with paper liners.
Whisk together the ground flaxseed and warm water in a large bowl and let it sit until thickened, about 5 minutes. Beat in the oil, milk, cream cheese, sugar, and vanilla. Use a wooden spoon to stir in the flour, oats, baking powder, salt, and mahlab until combined, being careful not to over-mix. Fold in the raisins.
Spoon the batter into the lined muffin tray and bake until a wooden pick inserted in the center comes out clean or with just a couple crumbs, about 20 minutes.
Cool completely on a wire rack before glazing.
Once the muffins are cool, whisk together all ingredients for the glaze. Drizzle the glaze on top and let it set before serving.
To keep this recipe vegan, use a vegan cream cheese alternative instead of regular cream cheese.