Dice onion

Add olive oil to pan

Add fennel and chili flake to pan and toast until fragrant 

Place tomatoes, onion, and salt in pan and cook on medium heat

As soon as your tomatoes start popping or breaking down, add chicken stock, balsamic vinegar, sugar to the pan

Once sugar is dissolved add Worcester and tomato paste and stir

Once the sauce has reduced down (this can take about 20 minutes), add in chopped garlic cloves to finish

Add Cayenne 1 tsp at a time, stir, and taste till you are satisfied with heat level

Serve with your favorite pasta and enjoy!