Make the margaritas by mixing together the jalapeño-infused tequila, orange-flavored cognac liqueur, lime juice and 1/4 cup simple syrup. Taste. If you’d like a spicier margarita, add more jalapeño and let it it sit a little longer. Pour into glasses and add lime slices and jalapeños for garnish. For a lighter margarita, fill the glasses 1/2 full and add sparkling water.