Preheat an oven to 350°.

Heat oil in a pan over medium heat. Add grape tomatoes and stir for half a minute. Remove it and set aside.

Add onions into the hot oil and saute until soft. Toss in the basil, stir quickly, and remove the pan from heat.

Whisk the eggs into a large bowl. Add the grape tomatoes, onions, basil, jalapenos, and grated Cheddar cheese. Mix until combined well.

Heat a skillet over medium heat. When hot, add olive oil and swirl around to coat the bottom and sides of the pan. Pour in the egg mixture and cook undisturbed for 4 minutes to let the bottom set.

Transfer the frying pan to the preheated oven and bake for 15-20 minutes or until the eggs are set in the centre.

Frittata is set, turn on the broiler and move the oven rack up to the top level. Remove the frittata from the oven, sprinkle the last 1/4 cup of Cheddar cheese over the top, and return the pan under the broiler for another couple of minutes until the cheese is bubbling and the top is nicely browned.

Remove the pan from the oven. Run a rubber spatula around the edges of the pan to loosen the sides, then slide onto a large serving plate. Cut into wedges and serve hot.

Wrap any leftovers in aluminum foil and reheat later at 350° for 12-15 minutes.