Bring to a strong boil, stirring occasionally, over high heat.

Stir and cook over medium heat for about 5 minutes until onions are light brown.

Cook, stirring often, over high heat, until they start to turn brown.

Cook and stir over medium heat for about 1 minute.

Add the cauliflower, and stir, still over high heat, for another minute.

Add the tomatoes and cook, stirring, over medium heat for 2 minutes.

Cook, stirring, about 3 to 4 minutes over medium-high heat.

Stir and cook for about 4 minutes over medium-high heat.

Add the flour and stir over the heat for 2-3 minutes.

Add the mushrooms and stir over medium-high heat until they begin to brown.