to roast your own garlic, peel 10 cloves and place inside a pocket of foil with 1 tablespoon of olive oil. fold over the edges of foil so that the garlic is completely encased and place onto a baking sheet in case oil drips out. roast in 350 F degree oven until gently browned ~ about 25-35 minutes.
let garlic cool, then combine with anchovies, mustard powder, lemon juice and egg yolks in a food processor. pulse until you have a consistent paste.
slowly add 1/3 cup olive oil while continuously running the food processor until aioli begins to lighten in color and starts to fluff up a bit - emulsified. you may have to adjust the amount of oil slightly, depending on size of egg yolks and anchovies.
finally, add cayenne, pepper and salt and pulse for a few more seconds. taste and adjust the seasoning as you like.
to serve, toast thick slices of crusty bread in the oven or in a cast iron pan with a tiny drizzle of olive oil (or better yet, grill bread on a BBQ!) top with a tablespoon of aioli, thick slices of fresh tomatoes, and if you like, a fillet or two of anchovies drained from oil. sprinkle with salt and pepper and munch away!