Preheat oven to 180C/355F. Grease 10cm/4inch tart pans. Make Fathead according to recipe adding garlic powder and salt to taste. Cut into 16 equal pieces and shape into rough balls. Roll a piece out into a circle shape big enough to fit a tart pan and line the pan with the pastry. To cut any excess on the edge, push the Fathead down onto the edge of the tart pan until it cuts through completely and pull the excess Fathead away.
Repeat with remaining Fathead and tart pans. You will find as you go that the Fathead has cooled down a lot, make sure to reheat it in the microwave when that happens (about 10 seconds) otherwise it will become hard to work with and won’t roll out smoothly. Prick holes all over the pastry in the bottom of the tart pans with a fork. Blind bake for 5 minutes.
While the pastry is baking, mix together ricotta and eggs with a stick mixer or similar until smooth and season with salt and pepper. Remove tart cases from oven and divide ricotta mix between them. Return to oven for 12 minutes or until filling is cooked and set. Don’t worry if they rise, they will go back down once out of the oven.
Melt butter in a frying pan and add onions. Sauté until soft, then add red wine vinegar and half the thyme. Sauté another few minutes, then add bacon, mix through and cook until heated. Remove from heat.
Divide and top the tarts with the onion and bacon. Sprinkle with remaining thyme. These can be served warm or at room temperature.