To prepare the rice, heat a tablespoon of olive oil in a medium saucepan over a low heat. Finely chop the garlic and add to the pan, sweating gently until tender.
Add the cauliflower rice and stir well. Cook for a minute to soften a little.
Add the tomato purée and the dried herbs and spices. Stir well.
Add the stock and mix well. Bring to a simmer and cook for 5 minutes until the liquid has evaporated.
Remove from the heat and stir through the grated cheddar.
Dice the tomato, scallion and radish and add to a small bowl. Season with a little salt and pepper and add the remaining olive oil and a tablespoon of chopped cilantro. Stir together.
Arrange the two lettuce leaves in serving bowls.
Divide the rice and tomato salsa between the serving bowls. Slice the avocado and add to the bowls.
Serve with sour cream and optionally a wedge of lime.