Preheat the oven to 425 F.
Remove the florets carefully from the head and place them in a colander. Try to remove large chunks of the florets instead of making them small. Rinse the florets well under running water and let it drain for few minutes.
Now cut the florets into bite size pieces. I tried to chop it in such way that each floret had a flat side to it. This way when we place the flat side down, it helps in roasting the florets faster.
Place the chopped pieces in a large bowl and add the olive oil, salt, pepper and cumin powder. Mix it well.
Place the florets, flat side down on a slightly greased baking sheet or a foil lined baking sheet. If there are any smaller pieces, leave it in the bowl and just place the uniform large pieces on the sheet. We will place the smaller pieces half way through the baking process so that they don’t burn.
Bake them for about 25 minutes, or until the florets are lightly roasted. Half way through the baking time, flip the pieces and at this time, add the smaller pieces that we had reserved (if any).
After 25 minutes, drizzle the lemon juice on the florets. Mix it to combine and then return to the oven for 10 more minutes.
Remove the sheet from the oven and add the cilantro. Toss it once and then serve the oven roasted cauliflower warm.