You can pit and pulp the cherries by hand, or by blending them coarsely and then picking out the pits with a spoon. NOTE: The cherry pits will float to the top while cooking, which can be easier. If I'm worried about losing too much pulp while scooping pits, I put the pits in a coarse sieve and pour aover them a small amount of hot water.
Mix cherry pulp and sugar, stir thoroughly. Can let sit for a half hour, if convenient.
Bring to a boil. Reduce heat. Stir constantly while cooking to avoid scorching and to help dissolve the sugar.
Add one tablespoon butter to settle the foam.
Add cinnamon and almond extract when sugar is dissolved.
NOTE: If you think the flavor might be too intense, try adding a small amount of hot water at this point - up to 1/4 cup. Adding a little water can make for smoother finished product, easier spreading, but will also take longer to gel.
Mix Certo liquid pectin and lemon juice in a small bowl. Add pectin mixture to bubbling mixture, and increase heat to bring to a boil again.
Stir vigorously while boiling for 3 minutes. Reduce heat.
Have 8-ounce or 4-ounce canning jars ready -- clean, lids convenient, jars resting full of hot tap water. Ladle cherry butter into jars with wide-mouthed canning funnel. With each jar, immediately screw on lid and flip jar over to sit on its lid for 5 minutes. After the five minutes, flip the jars back over. be careful not to burn your fingers.
Let sit at room temperature overnight before moving.