Step 1Using your fingers, lightly coat 5 (5-ounce) ramekins with oil.
Step 2Combine the cream, milk and sugar in a saucepan and cook over medium heat for 5 minutes. Add the almonds, whisk to combine and set aside. Allow the almonds to infuse for 2 hours. If using extract, heat the cream, milk and sugar, whisk to combine and then remove from the heat. When cool, add the almond extract.
Step 3Place the gelatin in a large stainless steel mixing bowl. Pour the water over the gelatin, adding more water if necessary to moisten all the gelatin.
Step 4Place the mixing bowl over a saucepan of barely simmering water and heat until the gelatin melts, about 30 seconds. Do not stir the gelatin, as it will scald on the sides of the mixing bowl. Turn off the heat and keep the gelatin warm.
Step 5Bring the almond mixture to a boil, pour over the gelatin and whisk to combine. Strain the mixture through a fine mesh stainless steel strainer to remove the bitter almonds, if you used them.
Step 6Ladle the mixture into the prepared ramekins and refrigerate for 6 to 8 hours.
Step 7To unmold the panna cotta, dip the bottoms in simmering water for a few seconds and invert onto a plate.