Caramelized onions: use a sharp knife and chopping board to peel and slice the onions into thin rings. Once done, use your fingers to separate the onions into individual rings. Next place a large sauce pan onto the stove top, add the olive oil and turn the heat to high. Add the onions and then use a wooden spoon to stir for 8-10 minutes. Once this initial cook time is up turn the heat to low. Next add the butter, balsamic vinegar and brown sugar then stir to combine. Let the onions keep cooking on low heat for an additional 15 to 20 minutes and stir them occasionally during this time. Once they have caramelized with the liquids being absorbed, turn the heat off.
Blitz: let the onions cool slightly, then transfer them into the food processor and blitz for mere seconds to chop them up slightly.
Preheat the oven: preheat the oven to 180°C / 350-375°F / Gas Mark 4-5. Note 4
Pastry: place a thawed sheet of puff pastry onto a clean, dry chopping board. Then use a pizza cutter to slice it into 16 even squares. Repeat for a 2nd sheet.
Muffin tin: grease a mini muffin tin with cooking spray. Then place the squares of pastry onto the top of each hole. Use a twisting motion to push the pastry down and into the base of the tin. Then repeat for all holes. Next use a fork and prick the base of each pastry cup.
Filling: use a teaspoon and spoon a small amount of the blitz caramelized onions into the pastry. Repeat for all holes. Next crumble the goat cheese over the top of the onions and repeat for all of the bites.
Bake: next place the mini muffin tin into the oven on the middle shelf. Let the goat cheese bites bake for 13 to 15 minutes. Once done, use an oven mitt to remove the muffin tin and place it onto a heatproof surface. Let the bites cool for a couple of minutes and then use a teaspoon to gently remove them and place on a wire cooling rack.
To serve; drizzle a little bit of balsamic glaze over the bites and sprinkle with thyme leaves.